TUFTS  COLLEGE  STUDIES,  Vol.  II,  No. 

(SCIENTIFIC    SERIES) 


THK    CKKKN    ALGAL;    OF    NORTH    AMERICA 
i3v  FRANK   Sn 


PtJI'.I.ISH!  K'LKS    1 1  YD]',    Ol.MSTl 

Tt     TS   COLLKGK,    MA- 

J  r  i ,  s 


UNIVERSITY  FARM 


TUFTS  COLLEGE  STUDIES 


(SCIENTIFIC  SERIES) 


VOLUME   II 


PUBLISHED  BY  THE  CHARLES  HYDE  OLMSTEAD  FUND 


TUFTS   COLLEGE,  MASS. 
1905-1909 


CONTENTS. 

NUMBER  I.     DECEMBER,  1905. 

I.  G.   E.  MARION:    Mandibular  and  pharyngeal  muscles 
of    Acanthias    and    Ruia.     (American    Naturalist,    39, 
pp.    891-920,    1905.)     15   text    figures  .         .  i 

NUMBER  II.     MAY,  1906. 

II.  F.  W.  THYNG  :    The  squamosal  bone  in  tetrapodous 
Vertebrata.      ( Proceedings   of    the    Boston    Society  of 
Natural  History,  32,  pp.  387-425.)     3  plates,  one  table, 
and  20  text  figures         .......       35 

NUMBER  III.    JULY,  1909. 

III.  F.  S.  COLLINS  :  The  Green  Algae  of  North  America. 

1 8  plates        .         .         .         .         .         ...         .         -79 


THE    GREEN    ALGAE    OF 
NORTH    AMERICA 


THE   TUFTS    COLLEGE    PRESS 


TUFTS  COLLEGE  STUDIES,  Vol.  II,  No.  3. 

THE   GREEN   ALGAE   OF   NORTH   AMERICA.* 
BY  FRANK  S.  COLLINS. 


TABLE   OF   CONTENTS. 


PAGE 

INTRODUCTION 80 

CLASS  HETEROKONT*.E.  92 

Order  I.  Confervales 92 

Family  i.  Confervaceae 92 

2.  Botrydiaceae 97 

3.  Chlorotheciaceae 99 

CLASS  CHLOROPHYCEAE.  100 

Order  I.  Conjugates <  101 

Family  i.   Desmidiaceae  (omitted)      101 

2.  Zygnemaceae 102 

3.  Mesocarpaceae 121 

Order  II.  Volvocales 127 

Family  i.  Chlamydomonadaceae 128 

2.  Volvocaceae 131 

3.  Tetrasporaceae 136 

Order  III.  Protococcales _._ 142 

Family  i.   Protococcaceae 142 

2.   Protosiphonaceae 153 

3..  Halosphaeraceae 154 

4.  Scenedesmaceae .  155 

5.  Hydrodictyaceae .  175 

Order  IV.  Ulotrichales 180 

Family  i.   Ulotrichaceae 180 

2.  Ulvaceae .  195 

3.  Prasiolaceae 217 

4.  Cylindrocapsaceae 222 

5.  Oedogoniaceae .  222 

6.  Chaetophoraceae 275 


Contributions  from  the  Harpswell  Laboratory  of  Tufts  College,  No.  32. 


8o  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

PAGE 

Family  7.  Herposteiraceae 310 

8.  Coleochaetaceae  ....  312 

9.  Trentepohliaceae     •    • 315 

Order  V.  Siphonocladiales 321 

Family  i.  Cladophoraceae 321 

2.  Gomontiaceae        370 

3.  Valoniaceae 371 

4.  Dasycladaceae 377 

5.  Sphaeropleaceae 384 

Order  VI.  Siphonales 385 

Family  i.  Codiaceae      »    •    •    •                    -  386 

2.  Bryopsiclaceae 402 

3.  Derbesiaceae 406 

4.  Phyllosiphonaceae    •    •            407 

5.  Caulerpaceae    ....                408 

6.  Vaucheriaceae 421 

List  of  works  to  which  reference  is  made  .    .                        .  433 

Description  of  plates  .    .                                                     ...  456 

Index  463 

INTRODUCTION. 

In  the  following  pages  it  is  intended  to  give  an  account  of  the 
green  algae  of  North  America,  with  as  much  detail  as  will  en- 
able the  student  to  recognize  the  species,  and  have  some  idea  of 
their  development  and  affinities.  North  America  in  this  sense 
includes  everything  from  the  Arctic  Ocean  to  th'e  Isthmus  of 
Panama,  including  the  West  India  Islands.  In  the  green  algae 
are  included  not  only  the  Chlorophyceae,  in  the  narrower  sense, 
but  also  the  small  class  of  the  Heterokontae.  On  the  other 
hand  two  families  are  omitted,  the  Desmidiaceae  and  the  Char- 
aceae;  the  former,  though  closely  related  to  the  other  Conju- 
gales,  has  generally  been  taken  as  a  separate  study,  for  special 
students  ;  to  include  it  with  as  much  detail  as  the  other  algae 
would  practically  double  the  size  of  this  work  ;  moreover  the 
American  desmids  are  not  well  enough  known  at  present.  The 
Characeae,  on  the  other  hand,  are  widel}'  separated  from  all 
other  algae,  representing  the  last  term  in  a  long  line  of  develop- 
ment, diverging  from  the  main  line  at  some  remote  time,  so 
remote  that  it  is  hard  to  guess  at  what  point  it  started. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  81 

Under  each  species  will  be  found  a  concise  description,  with  a 
record  of  the  localities  in  which  it  has  been  found ;  if  in  the 
United  States,  the  State  is  given,  but  seldom  any  more  exact 
location.  Reference  is  given  to  the  original  publication  of  the 
binomial,  also  to  some  good  plate  or  figure  ;  where  there  has 
been  distributed  in  some  set  of  exsiccatae  a  specimen  that  can 
be  identified  with  the  species  in  question,  reference  is  made  to 
this  ;  by  preference  use  is  made  of  the  Phycotheca  Boreali- 
Americana  of  Collins,  Holden  &  Setchell,  as  being  at  once  the 
fullest  for  American  algae,  and  the  most  accessible  for  Ameri- 
can students.  References  are  also  given  to  three  standard 
works  :  —  Harvey,  1852,  Farlow,  1881,  and  Wolle,  1887.  Where 
the  basis  of  treatment  of  any  family  or  genus  has  been  the 
monograph  of  any  author,  reference  is  made  to  such  monograph 
under  each  species.  In  special  cases  other  references  have 
seemed  desirable,  and  have  been  made. 

In  the  plates  there  will  be  found  at  least  one  figure  for  each 
genus ;  in  most  cases  these  are  taken  from  standard  works, 
often  from  the  original  description  of  the  species  represented. 
Where  a  choice  had  to  be  made  of  the  species  to  be  represented, 
in  some  cases  a  type  was  selected  other  than  the  one  most  famil- 
iar to  American  students  in  the  usual  text  books. 

It  has  not  seemed  necessary  to  furnish  any  glossary  of  botani- 
cal terms  used,  but  such  terms  as  are  special  to  the  forms  here 
described,  and  which  would  not  be  found  in  ordinary  botanical 
works,  have  been  included  in  the  index,  with  a  reference  to  the 
page  in  which  they  are  used  and  explained. 

In  the  present  imperfect  state  of  our  knowledge  of  the  green 
algae,  it  would  be  unsafe  to  make  deductions  as  to  distribution 
from  the  records  of  localities  here  given,  that  is,  as  to  their  ab- 
sence from  regions  not  noted.  In  fresh  water  algae  especially 
the  greater  part  of  our  territory  is  "terra  incognita."  Begin- 
ning at  the  north,  we  have  Greenland-,  with  a  limited  flora  of 
fresh  water  algae,  but  probably  as  completely  known,  thanks  to 
the  Danish  botanists,  as  that  of  any  other  region  of  the  same 
size  within  our  scope.  New  York  and  New  England  have  been 
considerably  explored,  and  there  are  some  few  records  from 
West  India  Islands.  The  fresh  water  algae  of  California  :  nd 


82  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Oregon,  near  the  coast,  have  been  collected  to  a  considerable 
extent  within  the  past  few  years  ;  but  for  the  rest  of  the  United 
States  there  is  only  the  record  of  a  few  species,  here  and  there, 
at  isolated  stations.  Lists  have  indeed  been  published,  at 
various  times,  of  local  floras,  but  when  the  attempt  has  been 
made  to  see  the  material  on  which  these  lists  were  based,  it 
has  usually  been  found  impossible  ;  in  the  few  cases  where  the 
material  was  accessible,  so  many  determinations  were  found  to 
require  correction  as  to  make  it  out  of  the  question  to  accept  the 
determinations  of  lists  whose  material  could  not  now  be  exam- 
ined. For  such  great  regions  as  Canada  and  Mexico  practically 
no  records  exist.  As  regards  marine  algae  the  case  is  not  quite 
so  bad.  They  follow  the  seashore,  and  it  is  easier  to  become 
familiar  with  the  narrow  strip  that  represents  their  distribution, 
than  with  the  great  enclosed  area  through  which  the  fresh  water 
species  are  to  be  found.  The  stretches  of  shore  of  which  we  are 
still  ignorant  are  not  disgracefully  long.  But  while  in  fresh 
water  collections  the  green  algae  constitute  the  greater  part, 
and  include  the  most  conspicuous  forms,  the  collector  at  the 
shore,  if  not  a  specialist,  is  likely  to  bring  away  the  showy 
brown  and  red  algae,  to  the  neglect  of  the  less  notable  green 
plants.  The  marine  flora  of  Greenland  is  as  well  known  as 
that  of  any  region  of  the  size ;  that  of  the  New  England 
coast  has  been  studied  for  many  years,  but  from  New  Jersey 
to  Florida,  published  records  are  quite  insignificant.  Some 
recent  observations  at  Beaufort,  North  Carolina,  at  the  lab- 
oratory of  the  U.  S.  Bureau  of  Fisheries,  which  the  authori- 
ties have  kindly  allowed  to  be  here  used,  to  some  extent 
supply  this  deficiency  ;  the  flora  of  Key  West  is  probably  as 
well  known  as  any  tropical  or  subtropical  flora  ;  lists  of  con- 
siderable completeness  have  been  published  for  a  number  of 
the  West  India  Islands.  But  beginning  with  the  west  coast  of 
Florida,  all  the  way  rotfnd  the  Gulf  of  Mexico  to  the  isthmus, 
we  have  practically  no  records  ;  the  same  is  the  case  on  the 
Pacific  coast  from  the  isthmus  to  California  ;  from  the  Mexico- 
California  boundary  north  to  the  Arctic  Ocean  observations 
have  pretty  well  covered  the  coast  line,  and  it  is  not  likely  that 
any  special  flora  has  escaped  our  notice.  This  does  not  mean 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  83 

that  we  are  fully  acquainted  with  any  region  ;  even  on  the  New 
England  coast,  which  has  been  studied  so  long,  species  new  to 
the  region  are  continually  turning  up.  . 

Not  only  in  comparing  different  regions,  but  in  comparing 
different  families  and  genera,  the  treatment  must  be  unequal. 
For  the  family  of  the  Oedogoniaceae,  for  instance,  we  have 
Hirn's  admirable  monograph,  based  on  an  ample  supply  of 
material,  American  as  well  as  foreign;  from  this  a  very  satis- 
factory account  of  this  family  can  here  be  given,  but  with  the 
proviso  that  species  described  by  Hirn  from  extra-American 
localities  will  probably  some  time  be  found  here.  Of  the 
genus  Chlamydomonas  Wille  has  published  a  thorough  re- 
vision, but  with  no  reference  to  American  material  or  locali- 
ties ;  little  attention  has  been  given  to  the  genus  here ;  only 
fresh  material  can  be  used  for  study,  so  that  practically  the 
genus  will  remain  unrepresented.  A  case  different  from  both 
these  is  presented  by  the  genus  Cladophora  ;  probably  more 
species  have  been  described  in  this  genus  than  in  any  other 
genus  of  algae,  except  possibly  some  of  the  minute  diatoms  and 
desmids.  Cladophoras  abound  everywhere,  in  fresh  and  salt 
water ;  herbarium  specimens  are  practically  as  good  for  pur- 
poses of  determination  as  the  living  plants  ;  and  yet  this  genus 
presents  more  difficulties  than  any  other  treated  in  this  work. 
Species  have  been  described  recklessly,  from  imperfect  material, 
often  with  little  or  no  consideration  of  what  had  before  been  de- 
scribed ;  the  plants  vary  much  in  response  to  environment,  and 
the  individual  plant  may  vary  much  at  different  stages  of 
growth,  but  except  in  a  very  few  instances  we  have  no  investi- 
gations to  show  just  what  forms  belong  in  the  same  life  cycle. 
These  three  instances  show  the  inequality  that  exists,  and  must 
long  exist,  in  our  knowledge  of  the  different  typ"es  about  to  be 
considered. 

Under  each  genus  will  be  found  a  key,  for  convenience  in 
identifying  plants  under  consideration.  These  keys  are  based 
as  far  as  possible  on  the  more  obvious  characters,  which  are 
not  necessarily  the  more  important  systematically,  but  the  sys- 
tematic characters  will  be  found  in  the  appropriate  place  under 
each  species.  The  characters  used  will  apply  only  to  the 


84  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

species  here  given,  and  would  mislead  if  used  for  species  of 
other  regions.  Each  distinction  in  the  key  being  founded  on  a 
single  character,  it  ma)'  sometimes  happen  that  one  will  be  led 
in  this  way  to  a  specific  description  differing  in  other  characters 
from  the  plant  in  hand  ;  in  such  case  it  may  be  that  it  is  a 
species  new  to  this  region,  and  reference  should  be  had  to  more 
general  works. 

At  the  end  of  the  descriptive  part  of  the  work  will  be  found  a 
list  of  the  works  referred  to,  arranged  alphabetically  by  authors, 
the  date  being  given  after  the  author's  name  ;  in  the  text  the 
reference  will  be  by  name  and  date  only,  full  particulars  of  title, 
etc,,  being  given  in  the  list.  This  does  not  attempt  to  be  a  full 
catalogue  of  works  on  American  algae ;  for  an  account  of 
these,  published  previously  to  1889,  see  De  Toni,  1889  ;  for 
works  with  special  reference  to  American  algae,  see  Tilden, 
1895  ;  later  than  these  dates  the  bibliographical  notes  in  Just's 
Botanischer  Jahresbericht,  Nuova  Notarisia,  Botanische  Cen- 
tralblatt  and  Hedwigia  will  be  useful,  as  also  the  Index  to 
American  Botanical  Literature  in  the  Bulletin  of  the  Torrey 
Botanical  Club.  The  labels  of  the  several  numbers  in  the  Phy- 
cotheca  Boreali- Americana  often  have  a  pretty  full  bibliography 
of  the  species. 

In  nomenclature,  the  rules  of  the  Vienna  Congress  have  been 
used  as  a  basis  ;  but  as  these  rules  were  adopted  completely 
only  as  to  the  higher  plants,  the  question  of  a  starting  point  for 
the  nomenclature  of  algae  being  referred  to  a  future  congress, 
it  has  seemed  unwise  at  present  unnecessarily  to  disturb  well 
established  names.  As  regards  classification,  the  general  ar- 
rangement is  that  of  Oltmanns,  1904,  but  with  some  variations 
in  detail. 

Anything  ol  the  character  of  the  present  work,  whatever 
name  appears  as  that  of  its  author,  represents,  if  it  is  of  any 
value,  the  work  of  many  individuals.  Limitations  of  space  pre- 
vent giving  exact  localities  and  collectors'  names  under  the 
several  species,  and  so  many  have  aided  the  writer  by  con- 
tributions of  material  from  localities  that  he  could  not  himself 
visit,  that  a  general  acknowledgement  of  their  assistance  must 
suffice.  But  a  few  names  must  be  mentioned.  To  Prof.  W.  G. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  85 

Farlow  of  Harvard  University  the  writer  owes  his  first  encour- 
agement in  the  study  of  algae  ;  for  this,  for  assistance  and 
advice  through  many  years,  and  for  the  opportunity  to  consult 
his  unrivalled  library  and  collections,  the  most  hearty  acknowl- 
edgement is  offered.  With  Prof.  W.  A.  Setchell  of  the  Uni- 
versity of  California  the  writer  has  been  associated  for  many 
'years  in  collecting  and  studying,  and  much  of  value  in  the 
present  work  is  due  to  his  contributions  and  suggestions.  That 
so  good  a  representation  can  be  given  of  the  green  algae,  marine 
and  fresh  water,  of  the  Pacific  coast  States,  is  chiefly  due  to  Dr. 
N.  L.  Gardner  of  Los  Angeles,  California,  an  acute  observer 
and  indefatigable  collector.  To  many  Kuropean  botanists 
thanks  are  due  for  information  as  to  types  and  for  materials 
for  comparison  ;  most  of  all  to  Dr.  Edouard  Bornet  of  Paris,  the 
value  of  whose  advice  and  assistance  is  equalled  only  by  the 
unfailing  promptness  and  courtesy  with  which  they  were  given. 
To  Prof.  J.  S.  Kingsley  and  Prof.  F.  D.  Lambert  of  Tufts 
College,  the  writer  is  indebted  for  opportunities  for  collecting 
and  study  during  the  seasons  he  has  been  at  the  Laboratory  at 
Harpswell,  Maine,  and  for  many  facilities  given  and  kindnesses 
shown  ;  the  plates  which  it  is  hoped  will  add  materially  to  the 
value  of  the  paper  are  also  their  work. 

No  one  can  know  as  well  as  the  writer  how  incomplete  the 
work  is,  and  how  likely  it  is  that  errors  will  be  detected  ;  but 
no  pains  have  been  spared  to  make  it  as  complete  and  accurate 
as  possible.  There  can  be  no  question  that  a  work  on  the  sub- 
ject has  been  needed  ;  if  this  will  stimulate  study  and  increase 
knowledge,  so  that  a  better  work  can  soon  take  its  place,  it  will 
have  justified  its  existence. 

Before  algae  are  studied  they  must  be  collected,  and  a  few 
hints  in  this  regard  may  be  of  use.  Only  the  green  algae  will 
be  taken  into  account  in  this  respect,  but  as  the  different  types 
of  green  algae  require  different  treatment,  practically  every 
contingency  as  to  other  types  of  algae  will  be  provided  for.  In 
temperate  regions  the  marine  green  algae  are  largely  littoral 
plants,  that  is,  inhabiting  the  zone  between  high  and  low  water 
marks ;  in  quiet  bays  and  pools  they  may  form  dense  floating 


86  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

masses,  but  very  few  have  to  be  sought  below  low  water  mark. 
In  the  extreme  north  the  temperature  and  the  shore  ice  permit 
practically  nothing  to  exist  uncovered  by  water,  and  all  algae 
must  be  obtained  by  dredging.  The  same  result  is  reached,  in 
part,  in  the  subtropical  waters  of  the  West  India  region,  but  by 
different  causes ;  tides  are  slight  and  irregular,  and  exposure  for 
any  length  of  time  to  the  intense  sunshine  would  be  fatal  to 
delicate  forms ;  here  also  one  must  look  below  the  surface. 

In  many  genera  of  marine  Chlorophyceae  the  individual 
plants  are  large  enough  to  be  easily  seen  (Ulva,  Cladophora, 
Udotea,  etc.)  but  for  the  greater  part  only  the  mass,  not  the 
individual,  can  be  distinguished  (Rhizodonium,  Codiolum,  etc.) 
while  others  appear  as  a  thin  film  on  wood  or  stone  (Pseudendo- 
clonium,  Pilinia,  etc.)  or  as  a  coloration  of  the  shell  in  which  they 
are  imbedded  (Gomontia).  Then  there  are  endophytic  forms 
(Bolbocolcon,  Chlorochytriu-ni)  not  at  all  manifest,  and  only  to  be 
found  by  dissection  of  the  host  plant.  These  conditions  being 
so  varied,  the  only  safe  course  for  a  student  is  to  collect  every- 
thing of  a  green  color  that  he  does  not  recognize.  Few  of  the 
marine  green  algae  are  specially  sensitive  ;  in  most  cases  they 
can  be  kept  a  reasonable  time  immersed  in  salt  water,  or  packed 
in  cloths  moistened  with  salt  water,  if  not  subjected  to  higher 
temperature  than  that  of  the  water  in  which  they  grew  ;  but  if 
plants  or  portions  of  plants  to  be  studied  must  be  kept  for  sev- 
eral days,  it  is  better  to  keep  them  in  salt  water  to  which 
enough  ordinary  formalin  (formaldehyde)  has  been  added  to 
make  a  three  per  cent,  solution.  Of  course  no  action  of  the 
living  plant  can  then  be  observed,  but  the  structure  is  main- 
tained practically  intact  for  months,  as  far  as  would  be  needed 
for  anything  described  in  this  work.  For  permanent  preserva- 
tion of  these  algae,  nothing  is  better  than  the  herbarium  form. 
In  many  genera  whatever  characters  are  needed  for  systematic 
purposes  can  be  obtained  from  herbarium  specimens,  and  in 
those  cases  where  characters  cannot  be  made  out  as  satisfac- 
torily in  the  dried  specimens  as  in  fluid  preparations,  at  any  rate 
whatever  is  available  continues  so  for  an  indefinite  time,  while 
it  is  only  too  common  to  find  a  fluid  preparation  worthless.  As 
regards  microscopic  slides,  they  can  be  prepared  so  as  to  show 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  87 

beautifully  some  particular  structure,  but  here  too,  permanence 
is  far  from  assured.  Moreover  the  slide  shows  just  the  one 
thing  in  the  one  position  ;  there  is  no  changing  or  moving  it. 

There  are  some  genera  of  tropical  algae  that  can  be  prepared 
for  the  herbarium  practically  the  same  as  flowering  plants  (cal- 
careous algae  like  Plalimcda,  and  coarse  non-calcareous  forms 
like  Avrainvilled)  by  pressing  between  driers  and  then  strapping 
or  gluing  to  herbarium  sheets.  Of  green  algae  of  temperate 
regions  Ulva  and  some  species  of  Cladophora  and  Chaetomorpha 
are  all  that  can  be  treated  in  this  way ;  most  species  that  are 
of  sufficient  size  for  the  individual  fronds  to  be  shown  (Bryopsis, 
most  Cladophoras)  should  be  mounted  on  paper,  and  the  paper 
attached  to  the  herbarium  sheet ;  the  plant  should  be  allowed 
to  spread  out  in  natural  form  in  a  shallow  dish  or  pan  of 
salt  water,  the  paper  placed  under  it  and  carefully  raised, 
until  it,  with  the  undisturbed  specimen,  is  lifted  out.  The 
papers  are  then  placed  on  driers,  specimens  up,  a  piece  of 
cotton  cloth  the  size  of  a  drier  laid  over  all ;  then  another  drier, 
specimens,  cloth,  etc.  After  this  the  process  is  much  as  for 
flowering  plants  ;  greater  or  less  pressure  according  to  the  char- 
acter of  the  specimens  ;  changes  of  driers  as  fast  as  they  become 
moist,  but  no  change  of  cloths ;  these  not  to  be  removed  until 
specimens  are  thoroughly  dry  and  ready  for  the  herbarium. 
The  heaviest  driers  should  be  used,  as  the  amount  of  moisture 
to  be  taken  xip  is  so  much  more  than  in  land  plants.  Frequent 
change  of  driers,  and  having  them  thoroughly  dry  when  used, 
will  add  much  to  the  value  of  the  specimens.  Nearly  all  algae 
prepared  in  this  way  will  adhere'to  the  paper. 

Those  forms  in  which  the  individual  plants  are  minute 
(Codiolum,  Prasinodadus)  of  course  cannot  be  treated  in  this  way  ; 
a  small  portion  of  the  thin  pasty  mass  can  be  spread  with  a 
knife  on  a  piece  of  paper,  and  then  dried  without  cover  or 
pressure.  It  is  sometimes  better  to  use  mica  instead  of  paper 
for  very  minute  forms  ;  they  are  then  ready,  when  moistened, 
for  microscopic  examination,  without  removing  from  paper  to 
slide.  Where  mica  is  used  and  a  large  number  of  specimens 
are  to  be  prepared,  it  is  often  convenient  to  add  more  water  and 
drop  from  a  pipette  on  the  mica. 


88  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

The  three  methods  just  given  practically  answer  all  require- 
ments for  marine  algae.  There  are  no  fresh  water  algae  that 
will  require  the  first  method;  a  few  (Cladophora,  Oedogonium) 
are  best  treated  by  the  second,  but  the  greater  part  require 
the  third. 

In  collecting  fresh  water  algae  it  will  be  found  to  be  the  rare 
exception  that  a  species  can  be  recognized  in  the  field  ;  one 
must  sample  everywhere  ;  at  first  the  abundance  of  new  forms 
will  be  so  great  that  a  few  such  samplings  will  give  materials 
for  hours  of  study  ;  later,  as  one  is  more  familiar  with  the  flora 
of  a  region,  the  proportion  of  novelties  becomes  smaller,  and 
after  a  while  one  is  satisfied  if  only  nine  out  of  ten  collectings 
are  thrown  away  after  a  hasty  examination.  On  the  other 
hand,  one  will  often  find  in  a  small  bottle  of  material  enough 
forms  for  days  of  study.  In  such  families  as  the  Zygnemaceae 
and  Oedogoniaceae  only  fruiting  specimens  are  accurately 
determinable  ;  in  all  but  a  few  of  the  larger  forms  the  micro- 
scope is  needed  to  decide  as  to  the  presence  or  absence  of 
fruit.  One  must  continue  to  collect,  though  the  proportion  of 
prizes  will  grow  steadily  less.  As  a  partial  recompense,  one 
often  finds  minute  epiphytic  algae  attached  to  the  larger  sterile 
plants  and  minute  plankton  forms  lying  loose  among  them. 
These  minute  unattached  forms  are  very  interesting,  and  have 
been  studied  but  little  in  this  country.  Wonderful  collections 
can  sometimes  be  made  by  drawing  a  fine  net  through  the 
water,  but  a  surprising  variety  can  also  be  found  entangled 
among  Utricidaria  and  other  water  plants,  or  adhering  to  the 
gelatinous  coating  on  stems  and  leaves  of  Pontcderia,  Brasenia, 
etc.  In  the  latter  case  the  material  can  be  scraped  off ;  in  the 
former  it  is  better  to  squeeze  the  plants  thoroughly,  remoisten 
and  again  squeeze  ;  this  can  be  repeated  many  times  before  the 
supply  of  algae  fails.  If  the  liquid  stands  in  a  jar  or  bottle,  in  a 
few  hours  the  algae  will  settle  to  the  bottom  ;  the  liquid  can  be 
drawn  or  carefully  poured  off.  If  then  formalin  be  added, 
enough  to  make  the  liquid  a  three  per  cent,  solution,  the  ma- 
terial can  be  studied  at  leisure. 

The  effect  of  formalin  is  not  permanent,  and  where  perma- 
nence is  needed,  other  preparation  must  be  used.  The  technic 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  89 

for  microscopic,  histological  and  cytological  work  is  now  so 
elaborate  and  varied  that  no  attempt  can  be  made  here  to  give 
any  details.  Perhaps  the  best  reference  for  it  is  Chamberlain's 
Methods  in  Plant  Histology. 

One  process  specially  useful  in  studying  herbarium  specimens 
of  green  algae  appears  not  to  be  generally  known  or  generally 
mentioned  in  the  technical  works,  and  it  may  be  well  to  note  it 
here.  When  a  herbarium  specimen  of  a  green  alga  is  mois- 
tened and  submitted  to  microscopic  examination,  it  is  often 
found  that  the  shape  of  the  cell  as  well  as  of  the  chromatophore 
has  been  lost  in  the  shrinking  in  drying,  and  not  recovered  by 
moistening.  If  then  the  bit  of  moistened  alga  is  laid  on  the 
slide,  in  a  drop  or  two  of  concentrated  lactic  acid,  then  warmed 
until  bubbles  appear  in  the  fluid,  it  will  often  be  found  on  put- 
ting on  the  cover  glass  and  examining  the  specimen,  that  the 
structure  of  the  original  has  been  much  restored. 

The  instructions  just  given  for  collecting  and  preparing  algae 
are  more  in  the  way  of  hints  and  suggestions  than  of  full  direc- 
tions. One  learns  by  practice,  and  not  much  any  other  way  ; 
the  "knack,"  the  little  contrivances,  will  soon  be  acquired. 
Those  who  prefer  fuller  directions  will  find  them  in  Harvey, 
1852,  Farlow,  1881,  Setchell,  1899,  Collins,  1899,  West,  1904. 

Many  kinds  of  algae  can  be  kept  alive  for  a  long  time,  with 
proper  care  as  to  fresh  water,  light  etc.;  development  can  be 
studied,  and  often  new  and  unexpected  forms  may  appear;  by 
adding  certain  substances  to  the  water,  reproductive  organs  of 
different  kinds  can  often  be  developed  ;  but  this,  as  well  as  the 
matter  of  pure  cultures,  opens  up  too  large  a  field  for  the 
present  work. 

As  regards  classification,  a  brief  notice  should  be  given.  Any 
statement,  even  approximately  full,  of  the  supposed  phylogeny 
and  relations  of  the  green  algae  would  require  more  space  than 
can  be  given  in  a  work  of  this  character.  The  most  plausible 
theory  now  is  that  the  green  algae  are  descended  from  the 
Flagellates,  a  class  of  organisms  that  has  been  claimed  (and  de- 
clined) both  by  botanists  and  zoologists.  The  Flagellates  are 
actively  moving  unicellular  organisms,  and  in  nearly  all  the 
green  algae  this  ancestral  form  reappears  as  the  zoospore,  the 


90     TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

permanent  condition  in  the  ancestor  being  only  the  transient 
condition  in  the  descendant.  Two  distinct  lines  seem  to  be 
traceable,  from  two  types  of  Flagellates  ;  one  producing  the 
small  class  of  Heterokontae,  the  other  the  remaining  green 
algae.  Some  authors  have  further  divided  the  latter,  and  as 
the  Heterokontae  derive  their  name  from  the  unequal  cilia  of 
the  motile  stage,  the  name  Isokontae  has  been  proposed  for 
algae  whose  motile  spores  have  two  equal  cilia  ;  the  Akontae 
for  those  with  no  motile  ciliate  stage,  and  the  Stephanokontae 
for  those  with  many  cilia  arranged  in  a  circle.  But  this  desire 
for  symmetry  seems  to  come  under  the  head  of  "  trop  de  zele  "  ; 
there  is  fully  as  much  reason  to  suppose  that  the  Conjugales 
(Akontae)  have  lost  the  motile  stage  possessed  by  their  ances- 
tors, and  that  some  at  least  of  the  multiciliate  organisms  are 
modifications  of  the  biciliate  type.  See  Davis,  1908. 

From  the  nature  of  the  case,  all  the  forms  here  to  be  described 
must  be  arranged  in  a  linear  series,  but  it  is  to  be  hoped  that 
no  one  will  suppose  that  their  relative  rank  can  be  determined 
by  their  position  in  the  series.  The  general  arrangement  is 
from  the  more  simple  to  the  more  complex ;  Order  A,  the 
simpler,  being  followed  by  Order  B,  the  more  complex  ;  and  in 
each  order  family  a,  the  simpler,  is  followed  by  family  b,  the 
more  complex;  but  it  is  almost  always  the  case  that  family  z, 
the  most  complex  of  Order  A,  is  considerably  in  advance  of 
family  a  in  Order  B.  A  glance  at  one  of  the  diagrams  that 
have  been  made  to  show  the  probable  filiation  of  the  different 
types  will  give  an  idea  of  the  complexity  of  the  matter.  Change 
is  not  necessarily  progress  ;  retrogression  is  often  evident.  The 
preservation  of  the  individual  or  of  the  type  may  be  secured  by 
very  many  appliances  or  adaptations,  thus  forming  diverging 
lines  of  development,  some  reaching  a  point  where  further 
progress  in  that  line  is  impossible,  others  continuing,  perhaps 
giving  off  lateral  lines  here  and  there.  All  schemes  of  showing 
these  tendencies  and  results  assume  the  former  existence  of  in- 
termediate forms,  now  extinct;  and  so  imperfect  is  our  knqwl- 
knowledge  of  what  remains,  that  it  is  evident  that  many  schemes 
may  yet  be  proposed  before  we  have  one  satisfying  all  the 
requirements.  No  attempt  will  here  be  made  to  give  any  such 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  91 

schemes  ;  those  interested  will  find  them  in  Bohlin,  1901  a  ; 
Blackman  and  Tansley,  1902;  West,  1904;  Oltmanns,  1905. 
The  general  statement  of  the  classification  used  here  is  this  :  — 
One  small  class,  the  Heterokontae,  including  algae  whose  motile 
cells  have  cilia  of  unequal  length  ;  whose  vegetative  cells  con- 
tain chromatophores  colored  yellowish  with  xanthophyll,  with- 
out pyrenoid,  and  whose  reserve  materials  are  in  the  form  of  oil 
rather  than  starch.  The  other  class,  the  Chlorophyceae,  in- 
cludes all  algae  with  true  chlorophyll-green  chromatophores, 
starch  reserves,  pyrenoids  usually  present,  and  whose  motile 
cells  have  cilia  of  equal  length.  The  Heterokontae  contain  but 
one  order,  Confervales ;  the  Chlorophyceae  six ;  Volvocales 
with  the  motile  stage  more  prominent  than  the  non-motile  ; 
Conjugates,  with  no  motile  stage ;  and  four  others  with  repro- 
duction by  various  sexual  or  non-sexual  motile  spores  or  by 
aplanospores,  evidently  a  modification  of  the  zoospores ;  in 
these  orders  there  is  so  much  variety  in  this  respect,  other  char- 
acters often  remaining  unchanged,  that  a  classification  based  on 
the  reproductive  bodies  would  seem  highly  artificial,  a  distinc- 
tion based  on  other  characters  more  natural.  So  we  have  the 
uninucleate  Protococcales,  the  cells  solitary  or  in  loose  colonies  ; 
the  membranaceous  or  filamentous  Ulotrichales,  also  with  uni- 
nucleate cells  ;  Siphonocladiales  with  multinucleate  cells  ;  and 
Siphonales  with  no  distinction  of  cells,  the  many  nuclei  distrib- 
uted all  through  the  interior  of  the  plant.  In  each  of  these 
orders  there  is  great  diversity  of  characters,  both  as  to  com- 
plexity of  structure  and  as  to  reproductive  characters ;  ex- 
tremely simple  vegetative  growth  being  accompanied  with  very 
elaborate  reproductive  mechanism  in  Oedogonium  and  Vaucheria, 
for  instance  ;  remarkable  variety  of  external  form  in  the  various 
species  of  Caulerpa,  with  no  reproductive  process  whatever 
known.  In  many  genera,  even  of  conspicuous  plants,  we  still 
have  to  write  "  reproduction  not  well  known  "  or  even  "  repro- 
duction unknown."  The  division  of  the  orders  into  families 
will  appear  as  they  are  reached  in  the  following  pages,  and 
requires  no  comment  here. 


92  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 


Class  I.     HETEROKONTAE. 

Motile  cells  with  two  cilia  of  unequal  length  ;  chromatophore 
more  or  less  distinctly  yellow  green;  reserve  material  oil,  not 
starch  ;  no  pyrenoids. 

Under  this  name  are  included  by  Oltmanns  and  others,  the 
family  Chloromonadaceae  of  the  Flagellates,  \vith  genera  of 
algae  supposed  to  be  derived  from  it ;  in  distinction  from  the 
great  body  of  green  algae,  whose  descent  is  from  other  forms  of 
Flagellates ;  the  name  is  based  on  the  unequal  length  of  the 
two  cilia,  one  of  the  two  being  sometimes  quite  imperceptible  ; 
though  the  distinction  may  appear  somewhat  artificial,  it  seems 
to  cover  a  distinct  line  of  descent  and  development.  Only  one 
order  of  algae. 

Order  CONFERVALES. 
KEY  TO  THE  FAMILIES  OF  CONFERVALES. 

i.     Terrestrial;    cell  vesicular,  with  branching  underground  prolonga- 
tions. 2.      BOTRYDIACEAH. 
i.     Chiefly  aquatic  ;  filamentous  or  unicellular,  without  branching  pro- 
longations. 2. 
2.     Unicellular  ;  cells  free  or  connected  by  gelatinous  strands;  sexual 

reproduction  by  gametes.  3.     CHLOROTHECIACEAE. 

2.     Unicellular  or  filamentous  ;  cell  wall  with  little  cellulose  ;  sexual 
reproduction  unknown.  i.     COXFERVACEAE. 

Family  I.     CONFKRVACEAE. 

Cells  free  or  united  in  attached  or  free  monosiphonous  fila- 
ments ;  cell  wall  with  little  cellulose,  mostly  pectin  ;  chroma  to- 
phores  usually  many,  disk-shaped,  always  without  pyrenoid, 
cells  containing  more  or  less  oily  matter  but  no  starch,  one  or 
more  nuclei ;  asexual  reproduction  by  zoospores  with  two  cilia 
of  unequal  length,  or  by  aplanospores  which  often  seem  to  take 
the  place  of  zoospores  under  certain  conditions  of  environment  ; 
all  plants  of  fresh  water. 

The  Confervaceae,  as  here  limited,  include  genera  that  have 
been  placed  at  widely  different  points  in  the  series  of  green 
algae,  and  their  association  here  is  by  no  means  free  from  ques- 
tions ;  some  of  them  have  been  reported  as  having  two  cilia  of 
equal  length,  some  as  having  only  one  ;  but  these  reports  ma}' 
be  due  to  imperfect  observations.  In  most  of  the  genera  there 
is  a  peculiar  stratified  arrangement  of  the  cell  wall,  by  which  the 


THE  GREEN  ALC.AE  OF  NORTH  AMERICA  93 

upper  part  fits  over  the  lower,  like  the  cover  on  a  pill  box  ;  in 
Conferva  this  results,  when  the  cell  breaks  open,  in  the  forma- 
tion of  the  so-called  H  sections,  formed  of  the  upper  half  of  one 
cell  and  the  lower  half  of  the  cell  above  it. 

KRY  TO  THK   GKNERA  OK   COXFKRYACKAR. 

i.     Cells  elongate.  2. 

i.     Cells  globose  or  subglobose.  3. 

2.     Cells  united  into  filaments.  4.     CONFRRVA. 

2.     Cells  solitary  or  attached  by  their  slender  bases. 

2.    OPHIOCYTIUM. 

3.     Cells  united  into  gelatinous  filaments.  3.     CHLOROBOTRYS. 

3.     Cells  solitary,  free.  i.     BOTRYDIOPSIS. 

i.     BOTRYDIOPSIS  Borzi,  1894,  p.  199. 

Frond  unicellular,  globose  or  subglobose,  uniuucleate,  free  ; 
containing  more  or  less  numerous  small  chromatophores  without 
pyrenoid.  Asexual  reproduction  by  numerous  zoospores,  show- 
ing amoeboid  changes  of  form  and  having  two  unequal  cilia. 

The  type  species,  B.  arhiza  Borzi,  has  not  been  found  in  this 
country,  but  two  new  species  have  been  described,  as  below. 
Nothing  is  known  of  them  other  than  the  descriptions  of  Miss 
Snow,  and  their  distinctness  from  the  European  species  may  be 
questioned. 

B.  ERIENSIS  Snow,  1903,  p.  384,  PI.  Ill,  fig.  XIII,  1-7.  Cells 
1 8-2 1  //.  diam.;  chromatophores  hexagonal  when  young,  elon- 
gate when  older:  zoospores  usually  16  or  32  in  a  cell,  escaping 
through  an  opening  in  the  cell  wall,  about  5X3  p,  with  red 
stigma,  and  only  one  cilium  showing  distinctly.  Fig.  i.  N.  Y. 

B.  OLEACEA  Snow,  1903,  p.  385,  PI.  Ill,  fig.  XII,.  i-io. 
Similar  to  B.  eriensis,  but  less  regularly  globose,  not  over  13  /* 
diam.,  chromatophores  densely  packed,  a  red  globule  near  the 
center  of  the  cell  ;  zoospores  5-8X3-5  p.  N.  Y. 

2.     OPHIOCYTIUM  Nageli,  1849,  p.  87. 

Cells  free  or  attached  to  water  plants,  multinucleate,  cylindri- 
cal or  claviform,  one  end  frequently  capitately  swollen  ;  straight, 
arched,  curved  in  S-form  or  spirally  ;  solitary  or  in  umbellate  or 
corymbose  families ;  at  each  end  rounded,  truncate,  or  mucron- 
ate,  or  rounded  at  one  end  and  with  a  stipe  or  spine  at  the 
other;  chromatophores  many,  parietal,  without  pyrenoid;  cells 
sometimes  containing  yellowish  oil  globules  ;  asexual  reproduc- 
tion by  aplanospores,  or  by  biciliate,  ovoid-oblong  zoospores, 
formed'  few  to  many  in  a  cell,  escaping  by  the  breaking  off  of 


94  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

the  cap-like  end  of  the  cell;  in  some  species  germinating  di- 
rectly at  the  summit  of  the  mother  cell,  in  others  entirely  inde- 
pendently. 

Not  uncommon  among  other  algae,  especially  the  unattached 
forms  ;  but  seldom  found  in  large  quantity.  The  present  treat- 
ment of  this  genus  follows  Lemmerman,  1899,  including  Scia- 
dium,  generally  kept  distinct  on  account  of  the  new  generation 
developing  at  the  summit  of  the  older  cell ;  but  as  th;s  same 
development  is  found  in  varieties  of  some  species  of  Ophiocytium, 
in  the  older  sense,  the  distinction  cannot  be  kept  up. 

KEY  TO  THE  SPECIES  OF  OPHIOCYTIUM. 

i.     Attached.  2. 

i.     Free.  3. 

2.     Cells  5-7  M  diam.,  stipe  10-14  f-  long-  6.     O.  gracilipes. 

2.     Cells  3-5  M  diam.,  stipe  2-3.5  p.  long.  5.     O.  arbtiscula. 

3.     Bearing  a  stipe  or  spine.  4. 

3.     Both  ends  rounded  or  truncate.  4.     O.  parvuluin. 

4.     Stipe  with  capitate  end-  i.     O.  tnajus. 

4.     Stipe  or  spine  acute.  5. 

5.     Spine  at  one  end.  2.     O.  cochleare. 

5.     Spines  at  both  ends.  3.     O.  capitatum. 

1.  O.  MAJUS  Nageli,   1848,  p.  89,   PI.  IV.  A,  fig.  2;  Lem- 
merman,   1899,  p.  29;  Phyk.  Univ.,  No.  19,  b.     Cells  solitary, 
8-17  /A  diam.,  spiral  or  curved  in  S-form ;    at  one  end  with  a 
straight  or  curved  stipe  with  capitate  end  ;  cells  often  with  hya- 
line or  yellowish  oil  globules.     Fig.  2.    Mass.  Europe. 

2.  O.  COCHLEARE  (Eichwald)  A.  Braun,  1855,  p.  54  ;   Wolle, 
1887,  p.  175,  PI.  CI/VIII,  figs.  8-14;   L,emmerman,  1899,  p.  30, 
PI.  Ill,  figs.   10-12;  P.  B.-A.,  No.  1424.     Cells  solitary,  5-8 /x 
diam.,  arched  or  spirally  twisted,  bearing  at  one  end  an  acute 
spine  1-12  n  long.     Me.,  Mass.  Europe. 

3.  O.   CAPITATUM  Wolle,    1887,  p.   176,   PI.  CLVIII,  figs. 
3-7;  Lemmerman,   1899,  p.  31,  PI.  IV,  figs.  16-18.     Cells  soli- 
tary, 5-10  ju.  diam.,  arched,  S-curved   or  spiral,  with  an  acute 
spine  5-7  /A  long  at  each  usually  swollen  end.     Mass.,  N.  Y. 

4.  O.  PARVULUM    (Perty)  A.   Braun,   1855,  p.   55;    Wolle, 
1877,   p.   176;   L,emmerman,    1899,   p.   33,   PI.   IV,   figs.   31-33; 
Rabenhorst,  Algen,  Nos.  516,  1546.     Cells  solitary,  3-9 /*  diam., 
straight,  arched  or  spiral,  rounded   at   each  end.     Greenland, 
Me.,  Mass.,  N.  Y.  Europe. 

Var.  CIRCINATUM  (Wolle)  Lemmerman,  1899,  p.  34,  figs. 
15-18;  O.  drcinatum  Wolle,  1887,  p.  176,  PI.  CL,VIII,  figs. 


THE  GREEX  ALGAE  OF  NORTH  AMERICA 


95 


15-18.     Cells  solitary,  10-13  /"•  diam.,  in  a  spiral  of  two  to  many 
turns,  both  ends  rounded.     Minn.  Europe. 

L,arger  than  the  type,  and  always  in  a  spiral,  usually  of  many 
turns. 

5.  O.  ARBUSCULA  ( A.  Br.)  Rabenhorst,   1868,  p.  68;  Lein- 
merman,  1899,  p.  28  ;   Sciadium  arbuscnla  A.  Braun,  1855,  p.  49, 
PI.  IV;   Wolle,  1877,  p.    174,  PI.  CLVII,  figs.    1-6  ;  Wittr.  and 
Nordst.,  Alg.  Exsicc.,  Nos.  401,  1360.     Cells  always  united  in 
families,  umbellate  or  corymbose,  straight,   3-5  /u,  diam.  ;  stipe 
slender,  2-3.5  /"•  l°ng>  connecting  the  lower  end  with  the  basal 
disk.   . 

Mass.   "  Specimens  from  three  or  four  states."  Wolle.    Europe. 

6.  O.  ORACiui'ES  (A.  Br.)  Rabenhorst,    1868,  p.  68;   Lein- 
merman,  1899,  p.  28;  Sciadiion  gracilipes  Wolle,    1887,  p.  175, 
PI.  CLVII,  figs.  7  and  8;   Bohlin,    i897a,  PI.  I,  figs.  27-32,  35, 
39,  40;   PI.  II,  fig».  59  and  60.     Cells  in  a  simple  umbel,  5-7  /*. 
diam.,  stipe  10-14  M  long,  to  the  disk-like  base.    Minn.  Europe* 

3.  CHLOROBOTRYS  Bohlin,  1901,  p.  34. 

Cells  globose,  with  severalfcd^sk-shaped  chromatophores  with- 
out pyrenoid,  with  more  or  less  oil ;  cells  2-16  united  by  a  hya- 
line tegument  ;  asexual  reproduction  by  short  cylindrical 
akinetes,  with  thickened  membrane,  formed  from  vegetative 
cells  ;  also  by  cell  division. 

Only  one  species. 

C.  REGuivARis  (West)  Bohlin,  1901,  p.  34,  fig.  9;  West, 
1904,  p.  254,  fig.  119.  Cells  globose,  10-27  ;u.  diam.,  united  by 
a  gelatinous  coating  into  families  up  to  90  p.  diam.  including 
the  coating,  cells  sometimes  in  contact ;  chromatophores  6-30  in 
a  cell ;  asexual  reproduction  by  division  of  a  cell  into  2-4 
daughter  cells,  also  by  akinetes.  Fig.  3.  Common  in  various 
parts  of  Europe,  and  reported  by  West  from  the  United  States. 

4.  CONFERVA  Linnaeus,  1737,  p.  326. 
Filaments  at  first  attached  by  a  special  basal  cell,  later  free  ; 

cells  uninucleate,  rarely  with  two  nuclei ;  chromatophores  disk- 
shaped,  two  to  many  in  a  cell,  without  pyrenoid,  producing  oil 
but  not  starch;  cell  wall  thin,  breaking  up  into  H  sections. 


*6.  CUSPIDATUM  (Bailey)  Rabeuhorst,  1868,  p.  68;  Wolle,  1887,  p.  176, 
PI.  CLVIII,  figs.  1-2;  Closterinm  cuspidatum  Bailey,  in  Ralfs,  1848,  p. 
219,  PI.  XXXV,  fig.  ir ;  Reinschiella?  cnspidafa  De  Toni,  1889,  p.  614. 
A  problematical  plant ;  it  is  doubtful  if  it  belongs  to  any  one  of  the  gen- 
era in  which  it  has  been  placed,  and  it  certainly  deserves  investigation. 
The  cells  are  crescent-shaped  with  rounded  ends,  like  a  broad  Clos- 
terium,  each  end  terminated  by  a  stout  spine.  The  cells  measure 
150X165  fj.,  the  spines  are  15  yu.  long. 


96  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Asexual  reproduction  by  2-ciliate  zoospores  without  red  stigma 
produced  1-4  in  a  cell ;  also  by  aplanospores. 

Under  the  name  Conferva,  dating  back  to  the  time  of  Pliny, 
Linnaeus  included  the  greater  part  of  the  filamentous  algae  ;  by 
the  steady  segregation  of  a  century  and  a  half,  it  has  been  re- 
duced to  a  small  group  of  fresh  water  algae,  and  is  here  taken 
in  the  extension  given  it  by  Lagerheim,  1889,  p.  194.  On 
account  of  the  impossibility  of  determining  what  plant  was  the 
'type,'  in  the  taxonomical  sense,  of  Linnaeus,  Hazen  proposes 
to  drop  the  name  Conferva  entirely,  substituting  the  Tribonema 
of  Derbes  and  Solier,  of  1856.  This  seems  rather  too  heroic 
treatment,  as  all  the  plants  included  in  Lagerheim's  Conferva 
have  long  borne  that  name,  would  certainly  have  been  included 
by  Linnaeus  under  it,  and  cannot  be  placed  in  any  other 
accepted  genus. 

KEY  TO  THE  SPECIES  OK  CONFERVA. 

I.     Chromatophores  2-4,  symmetrically  disposed.  2.     C.  minor. 

i.     Chromatophores  numerous.  •  2. 

2.     Filaments  3-6 /it  diam.  i.     C^bonibycina  forma  tennis. 

2.     Filaments  6-1 1 /a  diam.  i.     C.  bombycina. 

2.     Filaments  11-16  M  diam.  3.     C.  utriculosa. 

i.  C.  BOMBYCINA  Agardh,  1817^.78;  Wolle,  1887,  p.  142, 
PI.  CXXI,  figs.  8  and  9;  P.  B.-A.,  Nos.  620,  1278;  Tribonema 
bombydnum  Hazen,  1902,  p.  184,  PL  XXV,  figs.  1-3.  Forming  a 
yellowish  or  whitish  floccose  mass  ;  filaments  6-n  p,  diam.,  cells 
cylindrical  or  somewhat  inflated,  2-4  diam.  long ;  cell  wall  thin  ; 
Chromatophores  small  or  of  moderate  size,  several  in  a  cell. 
Fig.  4.  Maine  to  No.  Carolina;  Alaska  to  Vancouver  Island  ; 
probably  everywhere.  Europe. 

A  very  common  spring  plant  in  roadside  pools  and  brooks  ; 
the  disk-shaped  Chromatophores  distinguish  it  from  Microspora 
and  other  filamentous  algae  of  the  same  size,  and  the  dimensions 
separate  it  fairly  well  from  other  species  of  Conferva. 

Forma  tenuis  (Hazen)  nov.  comb.;  Tribonema  bombycinum 
forma  tenue  Hazen,  1902,  p.  185,  PL  XXV,  figs.  4-6;  Con- 
ferva bombydna  forma  -minor  Wille,  P.  B.-A.,  No.  621.  Cells 
3-6  /a  diam.,  2-12  diam.  long,  little  if  any  inflated;  chromato- 
phores  several,  small.  Greenland,  Maine  to  N.  J.  Europe. 

A  small,  delicate,  long-celled  form,  often  found  with  the  type  ; 
it  is  probably  only  a  condition,  but  has  quite  a  different  appear- 
ance. 


THE  GREEN  ALGAE  OK  NORTH  AMERICA 


97 


2.  C.   MINOR  Klebs,  1896,  p.  347,  PI.  II,  figs.  1-8;   P.  B.-A., 
No.    1327;     Tribonana  minus  Hazen,    1902,  p.   185,   PI.   XX  Y, 
figs.  7  and  8.     Cells  cylindrical  or  very  slightly  inflated,  5-6  /u, 
diam.,  2-4  or  even  6  diam.  long  ;  chromatophores  2  or  4  in  a  cell, 
arranged  in  pairs.     Mass,  to  N.  J.  Europe. 

In  habit  similar  to  C.  bombydna,  and  in  dimensions  not  unlike 
forms  of  that  species,  but  quite  distinct  in  the  symmetrical 
arrangement  of  the  2  or  4  chromatophores. 

3.  C.  UTRICULOSA  Kiitziug,  Decades,  No.  114;  Wolle,  1887, 
p.  140,   PL  CXX,  figs.  14-16;  P.  B.-A.,   Nos.  1071  and  1223; 
Tribonema  utriculosum  Hazen,  1902,  p.  186,  PI.  XXV,  figs.  9-11. 
Filaments  11-16  /x.  diam.;  cells  usually  inflated,  but  somewhat 
irregularly,  occasionally  cylindrical,    i}4~6  diam.    long,   rarely 
more  ;  chromatophores  large  and  often  crowded  ;  cell  wall  rela- 
tively thick.     Mass,  to  N.  J.;  Jamaica.  Europe. 

Our  largest  species,  having  thicker  cell  walls  and  larger 
chromatophores  than  the  others ;  the  cells  less  uniform  in  size 
and  shape  ;  the  Jamaica  plant  has  cells  up  to  12  diam.  long  ;  like 
the  other  species  chiefly  a  spring  plant. 

Many  species  originally  included  in  Conferva  will  now  be 
found  under  other  genera  ;  in  some  cases,  however,  the  descrip- 
tions are  not  sufficiently  full  to  determine  the  genus.  Among 
the  latter  are  C.  scsquipedale  Montagne,  1859,  p.  173,  from 
Louisiana;  C.  autiMarumKiitzing,  1853,  p.  15,  PI.  XL-V,  fig.  2, 
from  Trinidad  ;  C.  serpens  Kiitzing,  1849,  p.  372  ;  1853,  p.  15, 
PL  XL,VI,  fig.  2,  from  Texas;  C.  centrifuga  Agardh,  1854,  p. 
109,  from  Nicaragua. 

.  Family  2.     BOTRYDIACEAE. 

Unicellular,  multinucleate,  with  numerous  lens-  or  spindle- 
shaped  chromatophores ;  with  vesicular  part  above  ground, 
rhizoidal  part  below  ;  asexual  reproduction  by  uniciliate  zo- 
ospores,  and  by  aplanospores. 

Only  one  genus. 

BOTRYDIUM' Wallroth,  1815,  p.  153. 

Frond  stoutly  clavate  or  globose,  with  branched  lower  portion 
containing  protoplasm  ;  asexual  reproduction  by  uniciliate  zo- 
ospores,  formed  in  large  numbers  by  simultaneous  division  of  the 
cell  contents,  escaping  by  an  opening  at  the  summit ;  either  de- 
veloping into  vegetative  plants,  or  passing  into  resting  spores 
with  thick  membrane,  which  later  may  develop  vegetative  plants. 


98  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Under  special  conditions  round  or  ovoid  aplanospores  may  be 
formed  in  large  numbers  in  the  root  portions  ;  these  aplanospores 
may  either  produce  zoospores,  or  grow  directly  into  new  plants. 
After  much  confusion  in  regard  to  this  genus,  the  studies  of 
Rostafinski  and  Woronin,  1877,  appeared  to  settle  the  matter, 
and  since  that  time  the  genus  has  been  considered  as  consisting 
only  of  a  single  species,  exceedingly  polymorphous  in  its  adapta- 
tions to  varying  conditions.  But  the  more  recent  investigations 
of  Klebs,  1896,  and  Iwanoff,  1898,  show  that  apparently  at  least 
three  species  must  be  distinguished,  and  one  of  these  constitutes 
a  new  genus,  Protosiphon.  The  other  two  species  continue  in 
Botrydium.  There  is  no  way  of  determining  to  which  of  these 
three  species  any  record  of  Botrydium  granulatum  may  refer ; 
but  fortunately  all  three  species  are  included  in  the  material 
distributed  under  that  name  in  published  American  exsiccatae, 
and  can  be  described  here  ;  few  other  localities  than  those  of  the 
exsiccatae  can  be  given, 

KEY  TO  THE  SPECIES  OF  BOTRYDIUM. 
i.  Portion  of  cell  above  ground  clavate  with  thin  wall. 

i.     B.  granulatum. 
i.  Portion  of  cell  above  ground  spherical  with  thick,  stratified  wall. 

2.     B.  Wallrothii. 

1.  B.    GRANULATUM  (L,.)  Greville,  1830,  p.  196,  PL  XIX; 
Rostafinski  and  Worouin,    1877,   p.  16,   in  part,   PI.  I.;   Wolle, 
1887,  p.  155,  in  part,  PL  CXXXI,  figs.  1-9;   P.  B.-A.,No.  226. 
Exposed  portion   1-2  mm.   diam.,   broadly  clavate    or  obovoid, 
with  bright  green  contents  and  thin  wall,  tapering  below  to  the 
much  branched  subterranean  portion  ;  zoospores  formed  in  the 
upper  part,  10-20X5-8  n  ;  aplanospores  formed  in  the  lower  por- 
tion,  globose  or   oblong,  up  to  50  /x  diam.     On  moist  ground, 
especially  clay  ;  probably  generally  distributed.    Fig.  5.    Mass., 
N.  Y.,  Cal.  Europe,  So.  America,  New  Zealand. 

2.  B.   WALLROTHII  Kiitzing,  1839,  p.   387  ;  B.  granulatum 
Rostafinski  and  Woronin,  1877,  p.  16,  in  part,  PL  III,  figs.  25- 
28  ;   Tilden,  American  Algae,  No.  45,  in  part. 

Exposed  portion  globose,  rarely  equalling  i  mm.  diam.,  with 
dense,  dark  olive  green  contents  and  thick,  much  stratified 
membrane,  passing  without  transition  into  the  narrow,  cylindri- 
cal underground  portion,  which  for  some  distance  is  simple, 
then  branching  relatively  slightly  ;  the  wall  in  the  upper  part  of 
this  portion  is  so  thick  as  almost  to  close  the  opening.  On 
moist  ground.  Minn.  Europe. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  99 

The  specimens  distributed    by    Miss  Tilden  consist  of   this 
species  in  company  with  Protosiphqn  botryoidcs  (Kiitz.)  Klebs. 
Family  3.     CHLOROTHECIACEAE- 

Unicellular,  attached  ;  asexual  reproduction  by  (uniciliate  ?) 
zoospores  formed  one  or  more  in  a  cell ;  sexual  reproduction  by 
(uniciliate  ?)  gametes  formed  one  or  more  in  the  vegetative  cell, 
or  from  cells  developed  in  greater  or  less  number  within  the 
vegetative  cell ;  by  union  of  these  is  formed  a  normal  plant, 
either  directly  or  by  means  of  another  generation  of  zoospores. 
In  one  genus  there  is  a  vegetative  jdivision  of  the  cells,  the 
daughter  cells  attached  by  gelatinous  stalks  in  a  tree-like  colony. 
Fresh  water  plants.  Only  one  genus  represented  here. 
CHARACIOPSIS  Borzi,  1894,  p.  151. 

Cells  pyriform  or  ovoid,  with  several  chromatophores,  at- 
tached ;  erect  or  oblique,  with  longer  or  shorter  stipe ;  asexual 
reproduction  by  uniciliate  zoospores  (possibly  biciliate  with  one 
cilium  much  reduced)  formed  many  in  a  cell,  developing  directly 
into  a  plant  like  the  parent ;  sexual  reproduction  by  the  forma- 
tion of  numerous  cells,  with  membrane,  each  produ^ng  2-4 
zoogametes,  by  whose  conjugation  is  formed  a  resting'zygote, 
ultimately  developing  into  a  plant  like  the  parent. 

In  habit  the  species  of  this  genus  closely  resemble  species  of 
C/iaracium,  but  possess  a  sexual  reproduction,  and  have  zo- 
ospores with  only  one  cilium  or  with  merely  the  rudiment  of  a 
second  cilium.  In  Characium  there  is  only  one  chromatophore  ; 
in  Characiopsis  several  chromatophores  in  a  cell. 

KEY  TO  THE  SPECIES  OF  CHARACIOPSIS. 

i.     Without  basal  disk.  2. 

i.     With  basal  disk.  3. 

2.     Cell  ellipsoid  with  rounded  summit.  3.     C.  ellipsoidea. 

2.     Cell  lanceolate  with  acute  or  apiculate  summit.      2.     C.  minuta. 

3.     Stipitate,  outline  broadly  lanceolate  or  ovate.  i.     C.  acuta. 

3.     Sessile,  outline  narrowly  lanceolate,  acuminate,  more  or  less  oblique. 

4.     C.  subulata. 

1.  C.  ACUTA  (A.  Br.)  Borzi,  1894,  p.  153;   Characium  acutum 
A.   Braun,    1855,   p.  41,   PI.  V.  C.;    Wolle,   1887,  p.   177,   PI. 
CLIX,   fig.  2.       Cell    15-20X6-10  /*,   erect,   straight,   broadly 
lanceolate  or  ovate  in  outline,  equally  attenuate  each  way,  sub- 
acute,  opening  at  the  top  ;  stipe  slender,  5-10  /*  long,  expanded 
below  into  a  brownish  disk.     Pa.  Europe. 

2.  C.   MINUTA    (A.    Br.)    Borzi,    1894,    p.    152;     Characium 
minutiim  A.   Braun  in  Kiitziug,  1849,  p.  892  ;  1855,  p.  46,  PI. 


ioo    TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

V.  F.;  P.  B.-A.,  No.  1221.  Cell  17-25X5  /*,  lanceolate  in 
outline,  more  or  less  oblique,  subacute  or  apiculate,  apiculum 
straight  or  curved  ;  stipe  short,  base  not  expanded.  Fig.  6. 
Mass.,  Cal.  Europe. 

3.  C.  ELLIPSOIDEA  G.  S.West,  1905,  p.  288,  PI.  CCCCLXIV, 
fig.  8.     Cells  15-22X8-10  //.,  ellipsoid,   apex  obtusely  rounded, 
stipe  stout,  very  short,  without  basal  disk  ;  chromatophores  4. 
Barbados. 

The  stipe  is  so  short  that  the  cell  might  be  considered  practi- 
cally sessile. 

4.  C.  SUBULATA   (A.   Br.)   Borzi,    1894,  p.    152  ;    P.  B.-A., 
No.    1370 ;   Characium  subulatum   A.    Braun,    1855,  p.   47,    PI. 
V.   G.     Cell  12-20X4-5  M>  obliquely  lanceolate,  sessile,  with  no 
distinct  stipe,  but  with  sharply  contracted  base  and  basal  disk  ; 
apex  acuminate,  more  or  less  oblique;  cells  often  gregarious, 
with  confluent  basal  disks.     Cal.  Europe. 

Class  II.     CHLOROPHYCEAE. 

Alga*  of  true  green  color,  usually  producing  starch,  almost 
always  with  pyrenoid  ;  reproduction  in  most  cases  by  pyriform 
zoospores,  with  cilia  of  equal  length,  attached  to  the  smaller 
end;  mostly  two,  sometimes  four,  in  a  few  genera  many  cilia; 
zoogametes  of  similar  form,  with  twro  or  four  cilia. 

Motionless  spores  of  various  kinds,  and  sexual  reproduction 
by  oogonia  and  antheridia,  are  found  in  many  genera. 

KEY  TO  THE  ORDERS  OF  CHLOROPHYCEAE. 

i.     Frond  of  one  or  more  cells.  2. 

I.     Frond  usually  of  relatively  large  size,   multinucleate,  without  dis- 
tinction of  cells.  6.     SIPHONALES. 
2.     Vegetative  cells  ciliate  and  motile,  always  or  except  during  resting 
periods,  or  easily  passing  into  a  motile  condition. 

2.     VOLYOCAI.ES. 

2.     Vegetative  cells  motionless;  reproductive  cells  motile  or  not.    3. 
3.     Reproduction  by  zygospores  formed  by  the  union  of  two  non-motile 

cells.  i.     CONJUGATES. 

3.     Reproduction    by    zoospores,    zoogametes   or   aplanospores,    not   by 

zygospores  as  above.  4. 

4.     Cells  solitary  or  in  spherical  or  net-like  combinations. 

3.     PROTOCOCCALES. 
4.     Cells  forming  simple  or  branched  filaments  or  membranes,  rarely 

proliferously  branching  and  vesicular  cells.  5. 

5.     Cells    uninucleate,    chromatophore    usually    single,    disk-,    net-,    or 
star-shaped.  4.     ULOTRICHALES. 


THK  GRKKX  AI.C.AK  or  NORTH  AMERICA  101 

Cells    multiuucleate,   chromatophore    net-shaped,    or  of    numerous 
small  disks  in  a  cell.  5.     SII-IIDNOCI.  A  LI  \u:s. 


Order   I.     Coxu  CALLS. 

Grass-green  algae,  starch  forming,  with  cell  wall  of  cellulose, 
whose  cells  divide  only  in  one  direction,  and  are  either  isolated 
or  in  filaments  ;  not  incrusted  with  lime.  Zygospores  formed 
by  the  union  of  the  protoplasm  of  two  similar  or  only  slightly 
different  cells  '  '  aplanogametes  '  '  ;  after  a  longer  or  shorter  resting 
period  the  outer  membrane  of  the  spore  breaks,  and  a  new  vege- 
tative development  sets  in.  Thick-walled  resting  cells  "akin- 
etes  "  and  asexual  spores  "  aplanospores  "  sometimes  formed; 
no  motile  spores. 

The  Conjugates  are  distributed  all  over  the  world,  and  seem 
more  independent  of  geographic  limitations  than  other  algae.  Of 
the  47  species  of  Zygnemaceae  here  described,  all  but  three  occur 
in  Europe.  While  there  is  no  such  knowlege  of  these  plants  in 
Asia  and  Africa  as  there  is  in  Europe  and  America,  what 
species  have  been  observed  are  very  largely  the  familiar  forms 
of  the  better  explored  regions.  In  view  of  this  cosmopolitanism, 
any  localities  given  must  be  considered  as  indicating  where 
specimens  have  been  found,  not  as  limiting  the  range  of  distrib- 
ution. All  are  plants  of  fresh  water,  only  rarely  extending 
into  brackish  water. 

KEY  TO  THE  FAMILIES  OF  CONJUGATES. 

i.     Cells   usually  divided  by  a   constriction  into  symmetrical  halves; 

solitary  or  in  filaments  ;   the  cell  arising  from  the  germinating 

zygospore  either  taking  the  normal  form  or  producing  2-8  such 

forms.  (DESMIJMACEAE.) 

i.     Cells  cylindrical,  without  constrictions,  always  united  in  filaments; 

the  new  filament  always  formed  directly  from  the  zygospore.    2. 
2.     The  entire  protoplasmic  contents  of  the  conjugating  cells  uniting 

to  form  the  spore.  i.     ZYGNEMACEAK. 

2.     Only  a  part  of  the  contents  of  the  conjugating  cells  used  for  the 
spore.  2.     MESOCARPACEAK. 

The  family  Desmidiaceae  is  not  included  in  this  work. 
Rich  in  genera  and  species,  it  constitutes  a  special  field  apart 
from  other  algae,  and  for  its  proper  presentation  a  special 
treatment  would  be  needed.  The  two  other  families  are^closely 
related  and  distinctly  marked  off  from  all  other  green  algae  by 
the  character  of  the  fructification. 


102  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Family  i.     ZYGNEMACEAE. 

Filaments  sometimes  attached,  more  generally  free,  all  cells 
except  the  original  basal  cell  equally  capable  of  division  ;  fila- 
ments simple  or  rarely  with  short  rhizoidal  branches  ;  chromat- 
ophores  of  different  shapes  in  the  different  genera  ;  zygospores 
formed  by  the  union  of  the  contents  of  two  cells,  either  of  the 
same  filament  (lateral  conjugation),  or  of  distinct  filaments  (sca- 
lariform  conjugation)  ;  formed  either  in  one  of  the  two  cells,  or 
in  the  passage  between  them.  Spore  with  membrane  of  three 
layers,  of  which  the  middle  layer,  mesospore,  is  the  thickest  and 
usually  colored  brown  or  yellow  in  the  ripe  spore,  and  often  with 
pits  or  other  markings.  In  germination  the  two  outer  layers  are 
broken,  the  inner  forming  the  membrane  of  the  new  plant,  which 
at  once  divides  into  an  indivisible  basal  cell,  and  a  continuously 
divisible  filament  cell. 

KEY  TO  THE  GENERA  OF  ZYGNEMACEAE. 

i.     Two  cells  uniting  to  form  one,  before  the  formation  of  the  spore.     2. 
i.     Each  cell  dividing;  spore  then  formed  by  the  union  of  the  two  sec- 
ondary cells.  4.     ZYGOGONIUM. 
2.     Chromatophores  two,  star-shaped.  i.     ZYGNEMA. 
2.     Chromatophores  one  or  more,  parietal,  more  or  less  spiral. 

2.    SPIROGYRA. 
2.     Chrornatophore  an  axial  plate.  3.     DEBARYA. 

i.     ZYGNEMA  Agardh,  1814,  p.  33. 

Cells  cylindrical,  about  as  long  as  broad  or  somewhat  longer  ; 
dissepiments  smooth  and  even  ;  two  axillary  stellate  chromato- 
phores  in  each  cell,  each  with  a  pyrenoid,  the  nucleus  between 
the  two.  Conjugation  lateral  or  scalariform  ;  zygospore  formed 
either  in  the  connecting  tube  or  in  one  of  the  cells  ;  spore  with 
median  membrane  colored,  either  smooth  or  pitted  ;  outer  mem- 
brane colorless,  smooth  or  with  prominences.  Aplanospores 
formed  in  unchanged  vegetative  cells  and  similar  in  appearance 
to  zygospores.  Akinetes  formed  from  single  cells  taking  on  a 
thicker  membrane  and  richer  contents  ;  both  aplanospores  and 
akinetes  exceptional. 

KEY  TO  THE  SPECIES  OF  ZYGNEMA. 

i.     Spore  formed  in  the  tube.     Sect.     PECTINATA.  2. 

i.     Spore  formed  in  one  of  the  cells.  4. 

2.     Spore  with  thick,  lamellate  membrane.          2.    Z.  pachydermnm. 

2.     Spore  without  thick  lamellate  membrane.  3. 

3.     Spore  bluish.  3.     Z.  cyanospermnm. 

3.     Spore  brownish.  i.     Z.  pectinatnui. 

4.     Spore  with  smooth  median  membrane.        Sect.  LEIOSPERMA.     5. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  103 

4.  Spore  with  pitted  median  membrane.  Sect.  SCROBICULATA.  7., 

5.  Spore  bluish.  4.  Z.  chalybeospermum. 

5.  Spore  brownish.  6. 

6.     Vegetative  filaments  20-22  /j.  diam.  5.  Z.  leiospermum. 

6.  Vegetative  filaments  26-30  M  diam.  6.  Z.  insigne. 

7.  Spores  uniformly  globose.  7.  Z.  cruciatum. 

7.  Spores  usually  oblong.  8.  /..  stellinum. 

1.  Z.  PECTINATUM  (Vauch. )    Agardh,    1817,    p.    102;    De 
Bary,  1858,  p.  77,   PI.  I,  figs.  15-19;   PL  VIII,   Fig.   13;  Zygo- 
ooninm  pectinatum  Wolle,    1887,  p.  225,  PI.  CXLV,  figs,  i   and 
2;  P.   B.-A.,   No.   1216.     Vegetative   cells   30-37  p  diara.,   1-3 
diatn.  long  ;   membrane  at  first  thin,  later  with  a  thick,  gelati- 
nous sheath  ;  conjugation  scalariform  ;  spores  globose  or  broadly 
ellipsoid,  about  50  p.  diam.;  membrane  brown,  distinctly  pitted. 
Mass.,  N.  J.  Europe,  So.  America. 

Var.  ANOMALUM  (Ralfs)  Kirchner,  1878,  p.  126;  Z.  anoma- 
lum  var.  crassum  Wolle,  1887,  p.  224,  PI.  CXL,IV,  figs.  9-13. 
Cells  40-50  /u,  diara.;  membrane  very  thick.  Vermont,  Mass., 
Conn.  Europe. 

Var.  DECUSSATUM  (Vauch.)  Kirchner,  1878,  p.  127;  P. 
B.-A.,  1415.  Zygogonium  decussatum  Wolle,  1887,  p.  226,  PI. 
CXLV,  figs.  4  and  5.  Cells  18-20  p.  diam.,  membrane  not  con- 
spicuously gelatinous.  Mass.;  "Ponds,  stagnant  and  sluggish 
water."  Wolle.  Europe. 

Forma  TERRESTRE  (Rab.)  Kirchner,  1878,  p.  127;  P.  B.-A., 
No.  1365.  Membrane  thick,  dark-colored,  cell  shorter  than  in 
the  type  ;  on  ground  along  the  edges  of  ponds.  Mass.  Europe. 

2.  Z.  PACHYDERMUM  W.  and  G.  S.  West,  1895,  P-  26(>,  PI. 
XII,    figs.    1-16.     Filaments   flexuous,    somewhat    geniculate ; 
vegetative  cells   16-23  M,   usually  20  p  diam.,  2-3  diam.  long; 
membrane  up  to  5  /u.  thick  ;  short,  irregular,' rhizoidal  branches 
of  2-6  cells  frequent ;  conjugation  scalariform  ;  spores  globose, 
subglobose,    ellipsoid    or   of    irregular  shape,    25-35X19-26 /u.; 
membrane  up  to  6  yu.  thick,  lamellate  ;  aplanospores  similar  but 
somewhat  smaller  and  with  thinner  membrane.     In  warm  muddy 
water.     Dominica. 

Var.  CONFERVOIDES  W.  and  G.  S.  West,  1895,  p.  266,  PI. 
XIV,  figs.  1-6.  Cells  10-13 /A  diam.,  l~2  diam.  long;  reproduc- 
tion unknown.  With  the  type. 

The  irregularly  formed  spores  with  thick,  lamellate  walls  may 
be  a  result  of  the  peculiar  thermal  conditions  under  which  this 
species  occurs  ;  but  it  can  hardly  be  considered  as  a  form  of  any 
other  of  our  species. 


104  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

.3.  Z.  CYANOSPERMUM  Cleve,  1868,  p.  28,  PL  VIII,  figs. 
6-8.  Vegetative  cells  about  20  /j.  diam.,  2-9  diam.  long  ;  conju- 
gation scalariform  ;  spores  globose,  34-40  p.  diam.,  in  the  short 
tube;  membrane  bluish,  smooth.  Greenland. 

Northern  Europe. 

4.  Z.  CHALYBEOSPERMUM  Hansgirg,  i888a,  p.  257  ;  P.  B.-A., 
No.  808.     Vegetative  cells  24-27  /j.  diam.,  1-3  diam.  long,  fertile 
cells    shorter  ;     membrane    delicate  ;     conjugation    scalariform  ; 
spores  globose  or  subglobose,  about  35  /u,  diam.  ;   median  mem- 
brane bluish,  smooth  ;  cells  containing  spore  somewhat  inflated. 
Cal.  Europe. 

5.  Z.   LEIOSPERMUM  De  Bary,  1858,  p.  77,  PL  I,  figs.  7-14; 
Wolle,  1887,  p.  222,  PL  CXLJII,  figs.  1-3;   Rabenhorst,  Algen, 
No.  638.     Vegetative   cells    20-22  ^  diam.,  as  long  or  slightly 
more  ;  conjugation  scalariform  or  lateral ;  fertile  cells  somewhat 
swollen  and  shortened  ;  spores  smooth,  globose  or  broadly  ovoid, 
brownish,  23-30  p.  diam.,  escaping  from  the  cell  before  fully  ripe. 
Greenland,  Mass.  Jtitrope. 

6.  Z.   INSIGNE  (Hass.)   Kiitzing,    1849,  p.  444;    iS55a,  p.  5, 
PL  XVII,  fig.  i  ;   De  Bary,  1858,  p.  78,   PL  VIII,  figs.    14-16: 
Wolle,  1887,  p.  223,  PL  CXIvIII,  figs.  4-6;   P.   B.-A.,  No.  457. 
Vegetative  cells  26-30  /u.  diam.,  length  equal  to  diam.  or  up  to  2 
diam.  ;  cylindrical  or  swollen  on  one  side  ;  conjugation  scalari- 
form or  lateral ;  spores  30-32  //.  diam.,  brownish,  remaining  en- 
closed after  maturity  by  the  persistent  cell  wall.     Mass.,  N.  J., 
Cal.  J 'I  u  rope. 

Differs  from  the  preceding  species  chiefly  in  dimensions,  but 
also  by  the  different  behavior  of  the  ripe  spore. 

7.  Z.  CRUCIATUM  (Vauch.)  Agardh,  1817,  p.  102;   Kiitzing, 
18553,  p.  5,  PL  XVII,  fig.  4;  Wolle,  1887,  p.  224,  PL  CXLIV, 
figs,    i   and  2  ;     P.   B.-A.,    No.    758.     Vegetative  cells  35-54  p- 
diam.,  as  long  or  somewhat  longer;  conjugation  scalariform; 
spores   globose,   brown,   about  40  /u,  diam.,   median  membrane 
finely  punctate  ;  fertile  cells  not  swollen.     Mass.,  N.  J. 

Europe,  So.  America. 

8.  Z.  STELLINUM  (Miiller)  Agardh,  1824,  p.  77  ;  Wolle,  1887, 
p.  223,  PL  CXLIII,  figs.  7-17;   P.B.A.,  No.  1172.     Vegetative 
cells  25-36  fj.  diam.,  1-3  diam.  long;  conjugation  scalariform  or 
lateral;  spores  ovoid  or  oblong,  35-48X30-35^,  brown,  median 
membrane  with  rounded  pits  ;  fertile  cells  hardly  swollen.       Fig. 
7.     Greenland,  Mass.,  Conn.,  N.  J.  Europe. 

The  dimensions  are  for  the  type  ;    a  number  of  forms  have 
been  described,   in  some  of  which  the  cell  diameter  does  not 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  105 

exceed  10  p..     The  larger  forms  are  distinguished  from  Z.  cruci- 
atum   chiefly  by  the  form  of  the  spores,  ovoid  rather  than  glo- 
bose ;  also  by  the  somewhat  coarser  marking  of  the  membrane. 
2.     SPIROGYRA  Link,  1820,  p.  5. 

Cells  cylindrical,  once  to  many  times  as  long  as  broad  ;  dis- 
sepiments either  smooth  and  even  or  with  ring-like  projections  ; 
chromatophores  one  or  more  in  a  cell,  in  the  form  of  parietal, 
more  or  less  spirally  bent,  broad  or  narrow  bands,  each  contain- 
ing several  pyrenoids  ;  nucleus  in  the  middle  of  the  cell.  Con- 
jugation lateral  or  scalariform  ;  spore  formed  in  one  of  the  two 
conjugating  cells;  median  membrane  colored,  smooth  or  pitted  ; 
germinating  spore  producing  a  more  or  less  clavate  filament. 

A  genus  of  many  species,  of  world-wide  distribution  ;  the 
specific  distinctions  not  always  clear,  based  on  the  character  of 
the  dissepiments,  the  number  and  breadth  of  the  chromato- 
phores, the  size  and  form  of  the  spore,  the  character  of  its 
median  membrane,  the  inflation  of  the  fertile  cell,  and,  too  often, 
the  dimensions  of  the  filaments  ;  this  last  character  being  too  un- 
certain to  have  much  weight,  except  when  associated  uniformly 
with  other  characters.  The  size  and  shape  of  the  spore  is  of 
more  importance,  but  it  must  be  kept  in  mind  that  a  change  of 
position  in  the  cell  may  give  a  totally  different  aspect  to  the 
spore  when  seen  under  the  microscope.  An  ovoid  spore 
appears  circular  when  its  axis  is  in  the  line  of  vision  ;  and  a 
lenticular  spore  varies  from  circular  to  a  quite  narrow  oval, 
according  to  the  angle  at  which  it  is  seen.  Good  plates  are  of 
the  utmost  use  in  determining  species  of  Spirogyra  ;  the  best 
work  available  is  Petit,  1880.  Of  the  3.7  species  there  figured, 
32  are  given  in  the  following  pages,  and  there  is  no  reason  why 
the  remaining  five  should  not  be  expected  in  America.  In*  ad- 
dition to  the  zygospores,  parthenospores  are  sometimes  formed, 
the  usual  process  not  extending  to  the  union  of  the  tubes  from 
the  two  cells  ;  spores  formed  in  one  or  both  of  the  filament  cells. 
Aplanospores  occasionally  formed,  as  in  Zygnema. 

The  following  key  may  be  of  assistance  in  determining 
species,  but  in  a  rather  general  way. 

KEY  TO  THE  SPECIES  OF  SPIROGYRA. 

r.     Cell  conjugating  directly,  not  by  a  tube.  38.     5.  stictica. 

i.     Cell  emitting  a  tube.  2. 


106          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

2.     Dissepiments  plane.  3- 

2.     Dissepiments  replicate. 
3.     Chromatophore  single. 
3.     Chromatophores  two  or  more. 

4.     Spore  membrane  punctate.  27.     S.  pundata. 

4.     Spore  membrane  smooth.  5- 

5.     Fertile  cells  not  distinctly  swollen. 
5.     Fertile  cells  distinctly  swollen. 
6.     Cells  less  than  30  /x  diam. 

6.     Cells  30  fj-  diam.  or  more.  9- 

7.     Spore  ovoid,  slightly  longer  than  the  diam. ;  cells  22-25  M  diam. 

9.     S.  subsalsa. 

7.     Spore  ellipsoid,  2-3  times  as  long  as  the  diam. 
8.     Chromatophore  slender,  with  inconspicuous  pyrenoids. 

7.     S.  communis. 
8.     Chromatophore  slender,  with  many  large,  distinct  pyrenoids. 

3.     5".  Juergensii. 

8.     Chromatophore  broad.  f-     •$"•  longata. 

9.     Cells  30-48  fj.  diam.  2-     S.  porticalis. 

9.     Cells  48-70  M  diam.  8.     5.  condensata. 

10.     Fertile  cells  swollen  on  one  side  only. 
10.     Fertile  cells  swollen  on  both  sides. 

ii.     Cells  18-22  /x  diam.  21.     S.  gracilis. 

ii.     Cells  33-40  M  diam.  5-     S.  varians. 

12.     Chromatophore  slender. 
12.     Chromatophore  broad. 

13.     Cells  27-30  n  diam. ;  spore  30-33x33-45  M-  l8-     S.  affinis. 

13.     Cells  40-45  /x  diam.  ;  spore  about  47  /x  diam.,  of  varying  shape. 

6.     S.  fusco-atra. 

14.     Cells  11-13  M  diam.;  spore  about  20X30  M.          2O'     S.  flavescens. 
14.     Cells  24-27  /x  diam. 

14.     Cells  30-43 /x  diam. ;  spore  30-42X70-120  n.  22.  5.  lutetiana. 

15.     Spore  30X60-75  M.  4-     5.  catenaeformis. 

15.     Spore  24-26X38-50  M,  formed  without  conjugation. 

19.     5.  mirabilis. 

16.     Chromatophores  two,  rarely  three. 

16.     Chromatophores  regularly  three  or  more.  18. 

17.     Cells  27-40  /a  diam.  10.     5.  dedmina. 

17.     Cells  43-50  M  diam.  26-     ^  rf«*»«- 

18.     Spore  lenticular.  I9- 

18.     Spore  ovoid,  ellipsoid  or  subglobose. 

19.     Cells  100 /x  diam.  or  more.  16.     S.  maxima. 

19.     Cells  less  than  100  M  diam. 

20.     Fertile  cells  little  or  not  swollen.  15-     S-  orthospira. 

20.     Fertile  cells  distinctly  swollen.  25.     S.  bellis. 

21.     Cells  90-160 /x  diam. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA 


107 


21.     Cells  So  M  diam.  or  less. 
22.     Cells  150-160  /j.  diain.  ;  chromatophores  many. 


22.     Cells  loo-no  fj.  diam. ;  chromatophores  4-8. 

22.     Cells  90-100  M  diain. ;  chromatophores  3-4. 
23.     Cells  less  than  40  /*  diam. 
23.     Cells  50-80  M  diam. 

24.     Chromatophores  4. 

24.     Chromatophores  3,  rarely  2 


25.     Cells  50-65  fj.  diam. 
25.     Cells  70-78  fj.  diam. 

26.     Spore  60-72  M  diam. 

26.     Spore  about  50  M  diam. 
27.  '  Chromatophore  single. 
27.     Chromatophores  two  or  more. 

28.     Spore  membrane  punctate. 

28.     Spore  membrane  smooth. 
29.     Fertile  cells  little  if  any  swollen. 
29.     Fertile  cells  distinctly  swollen. 

30.     Filaments  9-23  M  diam. 

30.     Filaments  24-33  I*  diam. 
31.     Inflation  cylindrical. 
31.     Inflation  rounded  or  tapering  at  the  ends. 

32.     Cells  9-12  fj.  diam. ;  4-15  times  as  long. 

32.     Cells  15-18  M  diam.  ;  3-8  times  as  long. 

32.     Cells  18-21  /u  diam. ;  10-25  times  as  long. 
33.     Cells  24-30  /y.  diam. 


23- 

17.     S.  crassa. 
13.     S.  setifornris. 
12.    S.  jug  a  Us. 
24. 
25. 

24.     S.  fluviatilis. 
plant  of  brackish  water. 
10.    .*>.  decimina  var.  submarina. 
23.     S.  ternata. 
26. 

ii.     5.  nitida. 
14.     S.  parvispora. 
'28. 

34- 
37.     S.  protecta. 


32.     S. 


29. 

Weberi. 
30. 


33- 
34.     S.  groenlandica. 

32. 

28.     S.  tenuissima. 
29.     S.  inflata. 
30.     S.  Spreeiana. 
fertile  cells  quadrately  swollen. 

31.     S.  quadrata. 
33.     Cells  28-33  /*  diam. ;  fertile  cells  somewhat  rounded. 

33.     5".  Grevilleana. 

34.     Cells  30-33  p.  diam. ;  chromatophores  broad.      35.     S.  Hassallii. 
34.     Cells  39-42  /u  diam.  ;  chromatophores  slender.     36.     S.  insignis. 

Subgenus  EUSPIROGYRA  ;  conjugation  by  means  of  a  tube. 

Section  CONJUGATA  ;  dissepiments  plane. 

Subsection  DIPLOZYGA  ;  each  cell  emitting  a  tube. 

i.  S.  LONGATA  (Vauch.)  Kiitzing,  1843,  P-  279 ;  Petit, 
1880,  p.  20,  PL  V,  figs.  4  &  5;  Wolle,  1887,  p.  214,  PI. 
CXXXV,  figs.  9  &  10 ;  P.  B.-A.,  No.  510.  Filaments  20-36^ 
diam.,  cells  2-10  diam.  long,  chromatophore  single,  broad, 
bright  green,  making  2-5  turns  in  the  cell;  fertile  cells  not 
swollen ;  spores  broadly  ovoid  with  rounded  ends,  pale  yellow 
at  maturity,  twice  as  long  as  broad,  entirely  filling  the  width  of 
the  cell.  Mass.,  R.  I.,  N.  J.,  Colorado.  Europe,  So.  America. 

The  perfectly  cylindrical  form  of  the  fertile  cells,  barely  large 


io8  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

enough  to  contain  the  spores,    distinguishes  this  species  from 
others  of  the  same  general  dimensions. 

2.  S.   PORTICALIS  (Miiller)  Cleve,    1868,   p.   22,   PI.  V,  figs. 
8-13  ;   Petit,    1880,  p.  21,   PI.  V,  figs.  8-12  ;   P.  B.-A.,  No.  365  ; 
S.  quinina    Wolle,    1887,    p.    213,    PI.    CXXXIV,    figs.    14-17. 
Filaments  30-48  fj.  diam.,  cells  2-6  diam.  long;   chromatophore 
single,  quite  broad,  dentate,  bright  green,  making  3-4  turns  in 
the  cell ;  fertile  cells  little  or  not  at  all  swollen;  spores  ovoid 
or  subglobular,  yellowish  at   maturity,  i}4    diam.  long;  diam. 
up  to  42  p..     Mass.,  N.  J.,  Pa.,  Iowa,  Cal. 

Europe,  Asia,  So.  America. 

A  very  common  species,  often  forming  extensive  yellow-green 
masses  in  quiet  water  ;  very  mucilaginous ;  the  broad,  dentate 
spiral,  with  many  brilliant  pyrenoids,  is  characteristic. 

Forma  MINOR  Collins,  P.  B.-A.,  No.  1263.  Filaments  about 
42  p.  diam.  ;  spores  30-35  p.  diam.  Conn. 

3.  vS.  JUERGENSII  Kutzing,  1845,  p.  222  ;   Petit,  1880,  p.  16, 
PI.  V,  figs.  6  &  7  ;   Wolle,  1887,  p.  213,  PI.  CXLII,  figs  3  &  4  ; 
Rabenhorst,  Algen,   No.  1534.     Filaments  24-26  p.  diam.  ;  cells 
2^-5  diam.  long  ;  chromatophore  single,  slender,  delicate  green, 
with    pyrenoids   much   broader    than    the   spiral ;    fertile    cells 
slightly  swollen,  but  no  more  than  caused  by  the  spores  ;  spores 
30  p.  diam.,  ellipsoid,  twice  as  long  as  broad,  golden  color  at 
maturity.     Cal.  ;  according  to  Wolle,  generally  distributed. 

Europe . 

Nearly  allied  to  S.  porticalis  and  5".  communis ;  differing  from 
the  former  by  smaller  dimensions  throughout;  from  the  latter 
by  the  different  chromatophore,  and  by  the  shorter  and  stouter 
spore. 

4.  S.  CATENAEFORMIS  (Hass.)  Kiitzing,  1849,  p.  438;  Petit, 
1880,  p.  17,  PI.  Ill,  figs.  9-12;  P.  B.-A,  No.  361.     Filaments 
24-27  p.  diam.,   cells  2-5^   diam.  long;  chromatophore  single, 
quite  broad,  dentate,  making  1-6  turns  in  the  cell ;  fruiting  cell 
swollen,  up  to  36  p.  diam.  ;  spores  ellipsoid  with  rounded  ends, 
yellowish  at  maturity,  2-2^2  times  as  long  as  broad,  up  to  30 /u. 
diam.     Mass.,  Cal.  Europe. 

A  quite  variable  species,  but  not  difficult  of  recognition  by  the 
combination  of  characters  just  given. 

5.  S.  VARIANS  (Hass.)  Kutzing,  1849,  p.  439;   Petit,  1880, 
p.  19,  PI.   IV,  figs.    1-8;   Wolle,    1887,    p.   212,    PI.  CXXXIV, 
figs.   8-13  ;  P.  B.-A.,  Nos.  367,  962.     Filaments  33-40  p.  diam., 
cells  2-3  diam.  long;  chromatophore  single,   quite  broad,   den- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  109 

tate  or  serrate,  making  1-3  turns  in  the  cell  ;  fertile  cells  swollen 
only  oil  the  side  of  the  conjugation  ;  cells  in  filament  which 
have  not  conjugated  often  much  swollen  and  distorted;  spores 
ovoid  or  ellipsoid,  i>^-2^'  diam.  long;  diam.  33-38  p..  Me., 
Mass.,  N.  Y.,  X.  J.,  Iowa,  Wash.,  Cal.  AVmyV,  So.  America. 
A  polymorphous  species,  but  no  other  species  of  about  the 
same  dimensions  has  the  unilaterally  inflated  cells,  and  the  ir- 
regularly inflated  vegetative  cells. 

6.  S.  FUSCO-ATRA  Rabenhorst,  Algen,  No.  98  ;  Wolle,  1887, 
p.  215,  PI.  CXL,,  figs.  4-7.     Filaments  40-45  /j.  diam.,  cells  2-4 
diam.    long  :    cylindrical  or  slightly   constricted  at  the  nodes  ; 
becoming  blackish  with  age,  and  purplish  in  the  dried  speci- 
men ;    chromatophore   single,    making    2-3    turns   in    the    cell  : 
spores  polymorphous,  globose,  ellipsoid,  oblong  or  cylindrical, 
40-47  (j.  diam.     Pa.  1  Europe. 

This  species  is  included  with  some  doubt ;  the  description  by 
Wolle  is  meager  and  the  plate  little  more  satisfactory  ;  no  other 
American  record  is  known.  No  mention  is  made  of  the  black- 
ish or  purplish  brown  color  at  maturity,  from  which  it  has  its 
name,  and  neither  plate  nor  description  indicates  the  collapsed 
cells  surrounding  the  ripe  spores.  The  two-spired  filament  in 
the  figure  is  also  suspicious. 

7.  S.  COMMUNIS  (Hass.)  Kiitzing,  1849,  p.  439;  Petit,  1880, 
p.  16,  PI.  V,  figs.  1-3  ;    Wolle,  1887,  p.  213,  PI.  CXLII,  figs,   i 
and  2;   P.  B.-A.,  No.  1416.     Filaments  20-25  /A  diam.,  cells  3-5 
diam.  long;  chromatophore  single,  quite  slender,  making  1^-4 
turns  in  the  cell ;  fertile  cells  not  at  all  swollen  ;  spores  ellipsoid 
with   pointed    ends,   yellowish  at   maturity,    19-23  /A  diam.,  2-3 
times  as  long.     Mass.,  N.  J.  Europe,  So.  America. 

Often  forming  dense  masses  of  dark  green  color  in  quiet 
water  ;  soft  to  the  touch  but  not  mucilaginous  ;  best  character- 
ized by  the  uninflated  fertile  cells  and  by  the  long  spores  with 
pointed  ends. 

8.  S.  CONDENSATA  (Vauch.)  Kiitzing,  1843,  p.  279;   Petit, 
1880,  p.  22,   PI.  IX,  figs.  6-8;   Wolle,  1887,  p.  215;  Wittr.  and 
Nordst.,   Alg.    Exsicc.,    No.   247.      Filaments  48-54  /*  diam., 
cells  as  long  as  broad,  or  slightly  longer  or  shorter  ;  chromato- 
phore  single,   slender,    with   large   pyrenoids     making    ^-i^ 
turns  in  the  cell ;  fertile  cell  not  inflated;  spores  ellipsoid,  i^ 
diam.  long,  up  to  36  ^  diam.,  conjugation  usually  lateral. 

J-'.nropc,  So.  America. 


no          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Var.  RUSBYI  Wolle,  1887,  p.  215,  PI.  CXXXIX,  figs.  7-9. 
Filaments  62-75  f-  diam.  ;  otherwise  like  the  type.  New  Mex., 
N.  J.? 

It  is  not  clear  from  Wolle's  account  whether  he  had  observed 
the  type  in  this  country,  or  only  the  var.  Rusbyi,  The  N.  J. 
reference  is  in  any  case  doubtful,  only  sterile  plants  having  been 
observed. 

9.  S.  SUBSALSA  Kiitzing,  1845,  p.  222;  Wolle,  1887,  p.  212, 
PI.  CXLJ,  figs.  3  and  4.     Filaments  22-25  /"•  diam.,  cells   i-i)^ 
diam.  long;  chromatophore  single,  making  1^2-3  turns  in  the 
cell ;  fertile  cells  little  or  not  at  all  swollen  ;  spore  ovoid,  slightly 
longer  than  the  diam.;  diam.  18-20  /u,.     Florida.  Europe. 

Included  with  some  doubt ;  the  locality  is  not  indicated  as 
brackish. 

10.  S.   DECIMINA   (Miiller)  Kiitzing,    1843,   p.    279;     Petit, 
1880,    p.    25,    PI.    VIII,    figs.    1-3;    Wolle,    1887,   p.    216,    PI. 
CXXXV,   figs.  5  and  6;  Wittr.   and  Nordst.,   Alg.   Exsicc., 
No.    1372.     Filaments   34-40   /u,  diam.,    cells    2-4   diam.    long; 
chromatophores   2,  rarely  3,   quite  broad,  making  1-2  turns  in 
the    cell ;   fertile   cells   not   swollen ;    spores   broadly   ovoid   or 
almost  globular,  38X42-75  /A,  as  broad  as  the  filament.     Mass., 
Pa.,  Iowa,  Jamaica,  St.  Croix.  Europe,  Africa. 

Rather  common ;  usually  occurring  in  large  masses,  very 
mucilaginous. 

Var.  TRIPLICATA  Collins,  P.  B.-A.,  No.  960.  Chromato- 
phores uniformly  three  ;  spores  34-48X48-54  p. ;  otherwise  like 
the  type.  Mass.,  Cal. 

Var.  Submarina  n.  var.  Filaments  27-32  /A  diam.,  cells  3-6 
diam.  long;  chromatophores  2  or  3,  making  1^-3  turns  in  the 
cell;  spores  ellipsoid,  2-3  diam.  long,  31-37X56-120 /A  ;  fertile 
cells  swollen  just  enough  to  hold  the  spore.  Mass.,  Conn. 

Perhaps  a  good  species,  but  having  so  many  resemblances  to 
S.  decimina  as  to  indicate  that  the  differences  may  be  due  to  the 
station,  salt  marsh  and  brackish  pools,  an  unusual  one  for  a 
Spirogyra.  The  principal  distinctions  are  in  the  slender  fila- 
ments, longer  cells,  longer  spores  and  somewhat  swollen  fertile 
cells. 

ir.  S.  NITIDA  (Dillw.)  Link,  1833,  p.  262  ;  Petit,  1880,  p. 
28,  PI.  X,  figs.  6-10 ;  Wolle,  1887,  p.  217,  PI.  CXXXVII, 
figs.  7  and  8;  P.  B.-A.,  No  513.  Filaments  72-78  p  diam., 
cells  1^-3  diam.  long;  chromatophores  usually  5,  more  or  less 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  m 

broad,  sometimes  straight  and  parallel,  sometimes  making  a 
single  turn  in  the  cell ;  fertile  cells  little  or  not  at  all  swollen  ; 
spores  ellipsoid  with  tapering  ends,  yellowish  at  maturity,  1^-2 
diam.  long,  cliani.  60-72  /*.  Mass.,  Conn.,  N.  J.,  Iowa,  Cuba. 

F.iirope,  Africa. 

Forms  dark  green,  very  mucilaginous  masses  ;  filaments  crisp 
and  shining,  when  taken  from  the  water.  5.  diluta  Wood, 
1872,  p.  170,  PI.  XV,  fig.  2,  should  probably  be  included  in  this 
species. 

12.  S.  JUGALIS   (Fl.   Dan.)   Kiitzing,    1845,  p.   223;  Petit, 
1880,  p.   28,   PI.   XI,  figs.   3  and  4;   Wolle,    1887,  p.   219,   PI. 
CXXXVIII,    figs.    7    and    8  ;    Rabenhorst,    Algen,    No.    1049. 
Filaments  90-100  //.  diam.  at  the  nodes,  cells  i-i1/^  diam.  long, 
usually  swollen  near  the  middle  and  there  reaching  115  /A  diam., 
chromatophores  3  or  4,  quite  broad,  pale  green,  finely  dentate, 
with  many  large  pyrenoids,  and  making   1-2  turns  in  the  cell  ; 
fertile  cells  of  the  same  form  ;  spores  ovoid,  brown  at  maturity, 
1^2  diam.  long,  diam.  ioo-iio/tt.     Mass.  Europe. 

Not  uncommon,  forming  dense  masses  of  a  handsome  green, 
hardly  at  all  mucilaginous  ;  filaments  firm  and  crisped,  large 
enough  to  be  visible  singly.  The  swollen  vegetative  cells  give 
the  most  striking  character. 

13.  S.  SETIFORMIS   (Roth)   Kiitzing,    1845,   P-   223 :    Petit, 
1880,   p.    29,    PI.   XI,   figs,    i   &   2;   Wolle,    1887,   p.  219,  PI. 
CXXXVIII,  figs.   1-4;    Wittr.  &  Nordst.,  Alg.  Exsicc.,  No. 
747.     Filaments  100-110  ^  diam.,  cells  about  as  long  as  broad, 
sometimes  nearly  2  diam.  long  ;  4  rather  broad  chromatophores, 
irregular,    with    sinuate    margins    and    many   large   pyrenoids, 
making  l/2~i  turn  in  the  cell;  fertile  cells  not  swollen;  spores 
ellipsoid,  diam.  96-100 /*.     Mass.,  Pa.,  N.  J.  Europe. 

Quite  near  -6".  jugalis,  but  without  the  swollen  vegetative 
cells,  with  narrower  and  more  irregular  spirals,  and  somewhat 
smaller  spore. 

14.  S.  PARVISPORA  Wood,   1869,  p.   139;   1872,  p.   169,  PI. 
XV,  fig-.  7  ;  Wolle,  1887,  p.   221,   PI.  CXL,  figs.  8  &  9.     Fila- 
ments about  75 /A  diam.,  cells  2-4  diam.  long;  chromatophores 
4,    narrow,    making    il/4    turns    in    the   cell;    fertile   cells   not 
swollen;  spores  ellipsoid,  about  \Yi-2  diam.  long,  diam.  about 
50  p..    Florida. 

Quite  distinct  by  the  small  size  of  the  spores  in  proportion  to 
the  cells.  There  appears  to  be  no  record  of  it  but  the  original 
description. 


ii2  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

15.  S.  ORTHOSPIRA  Nageli  in  Kiitzing,  1849,  p.  441  ;   Petit, 
1880,   p.    30,    PI.   X,  figs.   4  and    5;     Wolle,    1887,   p.  218,  PI. 
CXXXVI,  figs.  10-11;  5.  majuscula  P.  B.-A.,  No.  511.     Fila- 
ments 60-66  /x  diam.,  cells  2-3  diara.  long  ;  chromatophores  7  or 
8,  very  slender,  pale  green,  usually  straight  and  parallel,  some- 
times inclined  and  making  a  quarter  turn  in  the  cell ;  fertile 
cells  little  or  not  at  all  swollen  ;  spores  at  maturity  brown,  len- 
ticular, about  72  ^  diam.,  by  48  p.  thick.     Mass.,.N.  Y.,  Pa., 
Minn.,  Dakota.  ttnrope,  So.  America. 

Usually  in  scattered  filaments  among  other  algae ;  while  in 
each  of  its  characters  it  resembles  some  other  species,  there  is 
no  one  which  combines  the  characters  of  numerous,  slender, 
straight  or  nearly  straight  chromatophores,  and  lenticular 
spores,  not  over  72  /u.  diam.  As  No.  285  of  Tilden,  American 
Algae,  is  distributed,  under  the  name  of  S.  majusciila  var.  brachy- 
iii c res,  a  plant  agreeing  with  6*.  orthospira,  except  that  the  cells 
are  somewhat  larger.  No  spores  were  found  in  the  specimen 
examined,  and  it  seems  safer  to  include  it  under  the  type  of  the 
species. 

16.  S.   MAXIMA  (Hass.)  Wittrock,  1882,  p.  57  ;   Wolle,  1887, 
p.   218,   PI.  CXXXIX,  figs.  3  and  4;  P.   B.-A.,   No.  512;  5. 
orbicularis  Petit,    1880,  p.  31,  PI.  XII,  figs,  i  and  2;   P.  B.-A., 
No.  1018.     Filaments   130-140  /u.  diam.,  occasionally  as  low  as 
118  /u, ;  cells  as  long  as  the  diam.  or  slightly  more  or  less  ;  chro- 
matophores 6  or  7,  narrow,  pale,  very  finely  dentate,  with  large 
pyrenoids,  making  half  or  three-quarters  of  a  turn  in  a  cell ;  fer- 
tile  cells  not    swollen ;    spores   lenticular,   brown   at   maturity, 
about  100-115  p.  diam.,  by  77-84  /u.  thick.     Pa.,  Cal. 

1 ',u  rope  i  So.  America. 

The  size  of  the  filaments  given  above  is  the  usual  dimension, 
but  considerably  larger  or  smaller  are  found,  in  exceptional 
cases ;  the  American  specimens  seem  to  be  usually  smaller  than 
the  European. 

Var.  INAEOUALIS  Wolle  in  Wittr.  and  Nordst.,  Alg.  Exsicc., 
No.  541  ;  1887,  p.  218,  PI.  CXXXVIII,  figs.  5  and  6.  Sporif- 
erous  filaments  about  So  ^  diam.,  conjugating  with  filaments 
about  125  p.  diam.,  spores  not  wider  than  the  cells  in  which 
they  occur.  Pa. 

Wittrock  and  Nordstedt  suggest,  Fasc.  21,  p.  31,  that  this  is 
possibly  a  hybridization  of  two  species. 

17.  S.  CRASSA  Kiitzing,    1843,    p.    280,    PI.    XIV,    fig.   4; 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  113 

Petit,  1880,  p.  32,  PI.  XII,  figs.  3  and  4;  Wolle,  1887,  p.  219, 
PI.  CLX,  figs.  1-3;  Phyk.  Univ.,  No.  440.  Filaments  150-160 
/u.  cliani.,  cells  1-2  diam.  long  ;  chromatophores  numerous,  rarely 
as  few  as  4,  often  10  ;  not  parallel,  rather  slender,  sinuate  at  the 
margin,  with  very  small  pyrenoids,  making  l/2-i  turn  in  the 
cell,  or  sometimes  nearly  straight ;  fertile  cells  not  swollen  ; 
spores  broadly  ovoid  and  flattened,  about  i^  diam.  long,  diam. 
140-150^.  Mass.,  Pa.,  N.  J.,  Iowa.  Europe,  So.  Anicr/m. 

The  largest  species  of  the  genus,  the  individual  filaments 
quite  distinct  to  the  eye,  firm  and  crisped,  somewhat  mucilagi- 
nous. 

1 8.  S.  AFFINIS  (Hass.)  Petit,    1880,    p.    18,    PI.    Ill,   figs. 
13-14;  P.  B.-A.,  No.  959.     Filaments  27-30  p.  diam.,  cells  1^2-3 
diam.  long;  chromatophore  single,  quite  slender,  making  1-3^ 
turns  in  the  cell,  often  forming  only  a  single  ring;  fertile  cells 
much  swollen,  often  nearly  or  quite  spherical ;    spores  ellipsoid, 
\-\Y?  diam.  long,  up  to  30 /A  diam.     Lateral  conjugation  more 
common  than  scalariform.     Jamaica,  Alaska.  Europe. 

Quite  distinct  by  the  uniformly  short  vegetative  cells,  and  the 
bullate  fertile  cells. 

19.  S.   MIRAUIUS  (Hass.)  Kiitzing,     1849,    p.   438;    Petit, 
1880,  p.   14,   PI.  Ill,  figs.  3  and  4;  Wolle,    1887,  p.  211,  PI. 
CXXXIV,  figs,  i   and  2;  Wittr.  and  Nordst.,   Alg.  Exsicc., 
No.    1377.     Filaments   24-27  n  diam.,   cells  4-10  diam.   long; 
chromatophore  single,   quite  broad,   making  4-7  turns  in  the 
cell ;    fertile  cells   swollen,   even   before  the   formation   of  the 
spores,  which  are  ovoid  or  ellipsoid,  24-26  p.  diam.,  ij^-2  diam. 
long  ;    and   are   formed   without   any  observable   conjugation, 
either  lateral  or  scalariform.     Maine,  Wis.  Europe,  Asia. 

The  spores  of  this  species,  though  in  appearance  like  zygo- 
spores,  are  more  properly  to  be  considered  aplanospores. 

20.  S.  FLAVESCENS  (Hass.)  Kiitzing,   1849,  p.  438 ;  Petit, 
1880,  p.    15,   PI.   Ill,   figs.   5  and  6;  Wolle,    1887,   p.  211,  PI. 
CXXXIV,  figs.  3  and  4;  Rabenhorst,  Algen  Sachsens,  No.  60. 
Filaments  11-13 /u.  diam.,  cells  3-4  diam.  long;  chromatophore 
single,  quite  broad,  yellowish  green,  making  1-2  turns  in  the 
cell  ;  fertile  cells  swollen  ;  spores  ovoid  with  rounded  ends,  yel- 
lowish when  mature,  20  p.  diam.,  i^  diam.  long.     Florida. 

Europe. 

Possibly  only  a  variety  of  the  following  species,  from  which  it 
differs  chiefly  in  its  smaller  diameter,  and  in  the  different  form 
of  the  fertile  cells.  Wolle  gives  a  larger  diameter  for  the  fila- 


ii4          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

ments  than  that  noted  above ;  his  plant  seems  intermediate  be- 
tween S.flavescens  and  5*.  gradlis. 

21.  S.  GRACILIS  (Hass.)  Kiitzing,  1849,  p.  438;  Petit,  1880, 
p.  15,  PI.  Ill,  figs.  7  and  8  ;  Wolle,  1887,  p.  211,  PL  CXXXIV, 
figs.   5-7,   P.   B.-A.,  No.    1418.     Filaments  1 8-21 /u.  diam.;  cells 
3-5  diam.  long  ;  chroma toph ore  single,  quite  broad,  rich  green, 
making  ^-3  turns  in  the  cell ;  fertile  cells  swollen  only  on  the 
conjugating  side,  the  other  remaining  straight;  spores  ovoid, 
yellowish  at  maturity,  diarn.  about  30  p,  length  about  double. 
Mass.,  Michigan.  Europe. 

22.  S.    LUTETIANA    Petit,     1879,    p.  97,    PI.  VI;    1880,    p.   21, 

PL  IV,  figs.  9-13;  Wolle,  1887,  p.  214,  PL  CXXXV,  figs.  7 
and  8  ;  P.  B.-A.,  No.  1065.  Filaments  30-36  ^  diam.,  cells  3-7 
diam.  long ;  chromatophore  single,  broad,  dentate,  dark  green, 
making  3-7  turns  in  the  cell ;  fertile  cells  sometimes  swollen, 
sometimes  cylindrical ;  spores  polymorphous,  globular,  ellipsoid, 
oblong,  cylindric-ellipsoid,  pyriform  or  reniform ;  yellowish  at 
maturity,  2-4  diam.  long;  diam.  30-43 /x.  Mass.,  Washington, 
Florida  ?  Europe. 

The  most  distinctive  character  of  this  species  is  found  in  the 
polymorphous  spores.  Wolle's  description  of  the  Florida  plant 
leaves  considerable  doubt  as  to  its  identity  with  Petit's  species. 

23.  S.  TERNATA  Ripart,   1876,  p.    162;  Petit,   1880,  p.  26, 
PL    VIII,    figs.   4-7 ;  Tilden,    American   Algae,    No.    159,    as 
6*.  neglcda.     Filaments  50-65  p.  diam.,  cells   1^-2  diam.  long, 
somewhat  swollen  at  the  middle  ;  chromatophores  three,  narrow, 
with  apparent  middle  line  uniting  the  pyrenoids,  making  1^-2 
turns   in   the   cell ;    fertile  cells   swollen    and   shortened,   often 
shorter  than  the  diam.,  so  that  the  spores  are  turned  at  right 
angles  to  their  usual  position  ;  spores  ovoid,  45-66  n  diam.,  i-i}4 
diam.  long.     111.,  Colorado.  Europe. 

This  species  is  nearly  allied  to  5".  neglect  a,  but  the  cells  are 
shorter,  especially  the  fertile  cells,  and  the  spores  are  often  so 
closely  set  that  they  are  side  by  side,  their  longer  axes  at  right 
angles  to  the  direction  of  the  filament. 

24.  S.  FLUVIATILIS  Hilse  in  Rabenhorst,  Algeu,  No.  1476  ; 
Petit,    1880,   p.    27,    PL    V,   fig.    13;  Wolle,    1887,   p.    216,  PL 
CXXXVI,   figs.    1-3;   P.   B.-A.,   Nos.    1217,    1417.     Filaments 
36  p.  diam.,  cells  5-6   diam.  long;    chromatophores  4,  slender, 
very  pale  green,  making  i^-2^|  turns  in  the  cell;  fertile  cells 
swollen  and  shortened;  spores  ovoid,  about  50X80  p.     Mass., 
Pa-  En  rope. 

No  spores  have  been  reported  from  the  European  localities, 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  115 

and  Wolle's  statement  as  to  Pennsylvania  localities  was  the 
first  record  for  spores  of  this  species ;  in  Massachusetts  it  was 
found  sterile,  attached  to  stones,  also  floating,  with  spores  like 
those  figured  by  Wolle. 

25.  S.  BELUS  (Hass.)  Cleve,  1868,  p.  18,  PI.  Ill,  figs.  2-5; 
Petit,  1880,  p.  31,  PI.  X,  figs.  1-3;  Wolle,  1887,  p.  217,  PI. 
CXXXVII,  figs.  5  and  6;  PI.  CXXXIX,  figs,  i  and  2  ;  P. 
B.-A.,  No.  359.  Filaments  65-80  //.  diam.,  cells  1^-3  diam. 
long  ;  chromatophores  5  or  6,  narrow,  with  large  prominent  py- 
renoids  ;  almost  straight,  or  making  half  to  three-quarters  of  a 
turn  in  a  cell  ;  fertile  cells  swollen  and  shortened ;  swelling 
sometimes  only  on  the  side  opposite  to  the  conjugation  ;  spores 
brown  at  maturity,  lenticular,  diam.  84-90  p.,  thickness  55-60  //.. 
Mass.,  N.  J.,  Pa.  Europe. 

26..  S.  DUBIA  Kiitzing,  18553,  p.  8,  PI.  XXIV,  fig.  4; 
Wolle,  1887,  p.  220,  PI.  CXXXV,  figs,  ii  and  12.  Filaments 
43-50  P-  diam.,  cells  i}4-2}4  diam.  long;  chromatophores  2, 
rarely  3,  narrow,  making  1-3  turns  in  the  cell ;  fertile  cells 
slightly  swollen  ;  spores  brownish  at  maturity,  ovoid-ellipsoid, 
about  40  /u.  diam.,  1-2  diam.  long.  Mass.,  Pa.  Europe. 

Var.  LONGIARTICULATA  Kiitzing,  18553,  p.  8,  PI.  XXV, 
fig.  i  ;  Wolle,  1887,  p.  220;  P.  B.-A.,  No.  961.  Cells  5  diam. 
long;  chromatophores  2  or  3.  British  Columbia.  Europe. 

Subsection  MONOZYGA  ;  only  one  cell  emitting  a  tube. 

27.  S.  PUNCTATA  Cleve,  1868,  p.  23,  PI.  VI,  figs.  1-4;  Petit, 
1880,  p.  24,  PI.  IX,  figs.  9-n  ;  Wolle,  1887,  p.  215,  PI.  CXU, 
fig8-    5'7-     Filaments   24-27  /u  diam.,    cells   6-12   diam.    long; 
chromatophore  single,  rather  slender,  with  few  pyrenoids,  mak- 
ing 4-7  turns  in  the  cell ;  fertile  cells  swollen  and  shortened  ; 
tube  issuing  from  only  one  of  the  conjugating  cells,  broadening 
until  it  reaches  the  surface  of  the  other  cell ;  spores  ellipsoid, 
yellowish    at    maturity,    1^-2    diam.  long,   about    36  /u.  diam.; 
median  membrane  finely  punctate.     N.  J.  Europe,  Asia. 

The  punctate  membrane  and  the  peculiar  formation  of  the 
tubes  amply  distinguish  this  from  all  our  other  species.  The 
latter  character  shows  a  more  distinct  sexual  differentiation 
than  in  other  species  of  the  genus. 

Section  2.     SALMACIS  ;  Dissepiments  replicate. 

28.  S.  TENUISSIMA  (Hass.)   Kiitzing,    1849,  p.  437;  Petit, 
1880,  p.  6,  PL  I,  figs.  1-3;    Wolle,   1887,  p.  207,  PL  CXXXII, 
figs.    1-3  ;   P.   B.-A.,    No.   456.     Filaments  9-12  /*  diam.;  cells 
4-12  diam.  long;  chromatophore  single,  slender,  making  3-5^ 


n6    TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

turns  iu  the  cell ;  fertile  cells  much  swollen,  vesicular,  not 
shortened,  extreme  diam.  37-42  p.  ;  spores  ellipsoid,  yellow  at 
maturity,  2  diam.  long,  diam.  about  30  p..  Mass.,  R.  I. 

Europe,  New  Zealand. 

The  smallest  of  our  species  and  easily  recognized. 

29.  S.  INFLATA  (Vauch.)  Kiitzing,  1843,  p.  279;  Petit,  1880, 
p.  7,  PI.  I,  figs.  4-6;   Wolle,    1887,  p.  207,  PI.  CXXXII,  figs.  6 
and  7;   P.  B.-A.,  No.  363.     Filaments  15-18  /u,  diam.,  cells  3-8 
diam.   long ;    chromatophore   single,   quite  broad,    making   3-8 
turns  in  the  cell ;  fertile  cells  much  swollen,  somewhat  shortened, 
42-48  p.  diam.;  spores  ellipsoid,  dark  yellow  at  maturity,  2  diam. 
long,  diam.  30-36 /*.     Mass.,  Conn.,  N.  J.  Europe. 

Resembles  6".  temiissima,  but  larger,  with  broader  and  more 
densely  twisted  spiral. 

30.  S.  SPREEIANA  Rabenhorst,  Algen,  No.  988  ;  Petit,  1880, 
p.  7,  PI.  I,  figs.  7-9  ;  Wolle,    1887,  p.  208,  PI.  CXXXII,  figs.  4 
and  5;    P.    B.-A.,    No.    1019.     Filaments   18-21   p.  diam.,  cells 
10-25  diam.  long;  chromatophore  single,  slender,  making  1^-4 
turns  in  the  cell ;  fertile  cells  swollen,  not  shortened,  30-42  p, 
diam.;  spores  ellipsoid,  yellowish  at  maturity,   2-3  diam.  long, 
diam.  up  to  36  p..     Mass.,  Washington,  Cal.  Europe. 

The  very  long  cells,  with  a  loose,  almost  inconspicuous  spiral, 
the  swelling  in  the  fertile  cells  tapering  to  each  end  of  the  cell, 
sufficiently  distinguish  this  species. 

31.  S.  QUADRATA   (Hass.)  Petit,   1874,  p.  41,  PL  I,  fig.    2; 
1880,  p.  8,  PI.  I,   fig.  13;    Wolle,   1887,  p.   208,  PL   CXXXII, 
figs.    8-10 ;    P.  B.-A.,    No.  366.     5.   bifaria  (Bailey)    Kiitzing, 
i855a,  p.  7,  PL  XXI,  fig.  3.     Filaments  24-27  p.  diam.,  cells  3-9 
diam.  long;    chromatophore  single,  broad,  making  1^-5  turns 
in  the  cell ;  fertile  cell  much  swollen,  up  to  54  p.  diam.,  appear- 
ing like  a  rectangle  with  rounded  corners ;  spores  ellipsoid  or 
cylindric-ellipsoid,  brown  at  maturity,  1^-2  diam.  long,  diam. 
42-48/11.     Mass.,  N.  Y.,  Pa.  Europe. 

Easily  recognizable  by  the  peculiar  shape  of  the  fertile  cells. 
According  to  Wolle,  S.  pulchella  Wood,  1872,  p.  164,  PL  XIV, 
fig.  2,  is  a  synonym  of  this  species.  The  plate,  though  appar- 
ently not  very  characteristic,  does  not  contradict  this  conclu- 
sion. Zygnema  bifaria  Bailey,  from  examination  of  authentic 
specimens,  agrees  fully  with  5.  quadrata. 

32.  S.  WEBERI  Kiitzing,  1843,  p.  279  ;  Petit,  1880,  p.  9,  PL  I, 
figs.  10-12;  Wolle,  1887,  p.  208,  PL  CXXXII,  fig.  u  ;   P.  B.-A., 
No.    368.      Filaments    22-28  p.  diam.,    cells   6-16    diam.    long; 


TIIK  GREEN  ALGAE  OF  NORTH  AMERICA  117 

chromatophore  single,  slender  and  loose,  with  large  pyreuoids, 
making  3/2-6  turns  in  the  cell ;  fertile  cells  not  swollen,  or  only 
enough  to  contain  the  spores,  which  are  ovoid,  1)^-2  diam. 
long,  diam.  26-30^.  Mass.,  N.  Y.,  N.  J.,  Pa.  Jturope. 

From  ^.  Grei'Ulcana,  which  this  species  considerably  re- 
sembles, it  is  distinguished  by  never  having  more  than  one 
spiral,  and  by  cells  little  if  at  all  swollen. 

33.  S.  GREVILLEANA  (Hass.)  Kiitzing,  1849,  p.  438;  Petit, 
1880,  p.  10,  PI.  II,  figs.  1-5  ;  Wolle,  1887,  p.  209,  PI.  CXXXII, 
figs.  12-13;  P.  B.-A.,  No.  362.     Filaments  28-33  f1  diam.,  cells 
3-10   diam.    long ;    chromatophore    broad,    usually   single   but 
occasionally  two  in  scattered  cells,  making  4-5,  sometimes  6-9 
turns  in  the  cell ;  fertile  cells  much  swollen  ;  spores  ovoid  with 
rounded  ends,  yellowish  at  maturity,  2-2^  diam.  long,  diam. 
30-36 /A.     Mass.,  N.  J.,  Iowa.  Europe. 

Often  forming  extensive  masses,  of  a  bright  green  color  and 
lubricous.  To  be  distinguished  carefully  from  5".  Weberi,  as 
noted  under  that  species. 

34.  S.    GROENLANDICA    Rosenviiige,   1883,  p.  37,  PI.  VII. 
Filaments   18-23   /u,   diam.,   cells   18-28    diam.   long;    chromato- 
phore single,  making  3-8  turns  in  the  cell  ;  fertile  cells  swollen 
in  the  middle,  the  swollen  part  cylindrical  or  sub-cylindrical, 
one-third  to  one-fourth  the  total  cell  length  ;    spores  ellipsoid, 
34-38X100-130  p.,  dark  brown;  conjugation  lateral;  partheno- 
spores  occurring  in  unswollen  cells,  the  spores  elongate,  but  of 
more  or  less  irregular  form,  nearly  as  large  in  diam.  as  the  cell. 
Greenland,  Mass. 

Resembling  somewhat  6*.  quadrata  and  .5".  Spreeiana  ;  from  the 
former  it  differs  by  the  much  longer  cells,  the  swelling  occupy- 
ing only  a  small  part  of  the  whole  length  ;  from  the  latter  by  the 
swelling  being  sharply  marked  off  from  the  unswollen  part  of  the 
cell,  and  also  by  the  color  of  the  spore,  dark  brown  at  maturity 
instead  of  yellow. 

35.  S.  HASSALLII  (Jenner)  Petit,    1880,   p.   12,  PI.  II,  figs. 
6-8;  Wolle,    1887,    p.    210,    PI.    CXXXIII,    figs.    5-7;     Phyk. 
Univ.,  No.  732.     Filaments  30-35  /*  diam.,  cells  4-8  diam.  long  ; 
chromatophores  2,  quite  broad  and  loose,  making  1^-2  turns  in 
the  cell;    fertile  cells  slightly  swollen;    spores  ellipsoid,   1^-3 
diam.   long,  diam.  42-48  p.,  yellow  at  maturity.     Mass.,    low^a. 

Europe. 

36.  S.  INSIGNIS  (Hass.)  Kiitzing,  1849,  p.  438;  Petit,  1880, 
p.  13,  PI.  Ill,  figs  i  &  2;  Wolle,  1887,  p.  210,  PI.  CXXXIII, 


u8          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

figs.  8  &  9;  Wittr.  &  Nordst.,  Alg.  Exsicc.,  Nos.  958,  1373. 
Filaments  38-45  /*  diam.,  cells  4-12  diani.  long  ;  chromatophores 
3,  very  slender,  pale  green,  with  large  pyrenoids,  making  ^-i^ 
turns  in  the  cell ;  fertile  cells  much  swollen  and  shortened  ; 
spores  ellipsoid,  1^2-3  diam.  long,  diam.  up  to  48  p..  N.  J.,  Pa. 

Europe. 

Our  only  species  with  replicate  cell  walls  and  three  spirals ; 
the  typical  form  quite  distinct,  but  connected  with  6".  Hassallii 
by  the  following  variety. 

Var.  HANTZSCHII  (Rab.)  Petit,  1880,  p.  13  ;  6".  Hantzschii 
Wolle,  1887,  p.  211,  PL  CXXXIII,  figs.  10-11  ;  P.  B.-A.,  No. 
364.  Chromatophores  usually  2,  occasionally  3.  Mass.;  Pa. 

Eiirope. 

Petit  notes  that  in  the  conjugation  in  this  variety,  filaments 
with  two  spirals  frequently  unite  with  filaments  of  three  spirals  ; 
in  this  case  the  three  spiral  cells  always  function  as  female, 
receiving  the  contents  of  the  two  spiral  cells  and  developing  the 
spore. 

37.  S.  PROTECTA  Wood,  1872,  p.  165,  PL  XIV,  fig..  3;  S. 
elcgans  Cleve  in  Wittrock,  1868,  p.  190;  S.  calospora  forma 
gradlior  Cleve,  1868,  p.  26,  PL  VIII,  figs.  2  and  3  ;  S.  calospora 
Petit,  1880,  p.  ii,  PL  II,  figs.  11-13;  Wolle,  1887,  p.  209,  PL 
CXXXIII,  figs.  3  and  4;  P.  B.-A.,  No.  360.  Filaments  32-36 
fji  diam.,  cells  6-12  diam.  long;  chromatophore  single,  slender 
and  loose,  making  4-5  turns  in  the  cell ;  fertile  cells  little  or  not 
at  all  swollen,  not  over  42  /u,  diam.;  spores  ellipsoid  or  cylindric- 
ellipsoid  with  rounded  ends,  yellow  at  maturity,  2-3  diam.  long, 
diam.  40-42/1.;  median  membrane  punctate.  Fig.  8.  Mass., 
Conn.,  N.  J.,  Mich.  Europe. 

The  only  species  occurring  with  us  which  has  the  replicate 
cell  walls  and  the  punctate  membrane.  It  is  a  beautiful  object 
under  the  microscope,  the  yellow  spores  with  their  elegant  mar- 
gin standing  out  strongly  against  the  dark  green  filaments. 
In  Cleve's  description  of  5".  calospora  two  forms  are  distin- 
guished;  forma  a  major,  forma  b  gradlior ;  afterwards  the  sec- 
ond form  was  raised  to  specific  rank  as  S.  clegans,  but  this  name 
cannot  stand  as  there  is  an  earlier  S.  elcgans  Bonhome,  1858, 
p.  6.  The  genuine  5".  calospora,  S.  calospora  forma  major  of  the 
original  description,  appears  to  be  unknown  outside  of  Scar.di- 
navia,  but  .5".  protecta  seems  common  in  this  country  as  well  as 
in  various  parts  of  Europe.  Wittrock  considers  5*.  elegans  to 
be  the  same  as  Vaucher's  Conjugata  longata,  but  the  evidence 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  119 

seems  hardly  sufficient  to  justify  transferring  the  name  to  this 
species,  from  the  so  long  recognized  >S.  longata  Kiitz. 

Subgenus  SIROGONIUM.  Cells  directly  conjugating,  without 
formation  of  tube. 

38.  S.  STICTICA  (Eng.  Bot.)  Wille,  1884,  p.  34;  P.B.-A.,No. 
1366  ;  Sirogonium  sticticiim  Petit,  1880,  p.  34,  PL  VII,  figs.  6-8; 
Wolle,  1887,  p.  222,  PI.  CXU,  figs.  8-10.  Filaments  38-54  /u. 
diam.,  cells  2-4  diam.  long;  chromatophores  3-4,  narrow,  paral- 
lel and  straight  or  slightly  curved  ;  fertile  cells  shortened  but 
only  ver)r  slightly  swollen  ;  conjugation  of  cells  direct,  by  gen- 
icular  bending  towards  each  other  of  two  filaments,  the  female 
filament  larger  than  the  male  ;  each  of  the  original  filament  cells 
dividing  into  two,  rarely  three  in  the  male  filament ;  of  these 
cells  two,  one  from  each  filament,  unite  to  form  the  spore,  the 
others  remaining  sterile  ;  spores  ellipsoid,  yellowish  at  maturity, 
\y2  diam.  long,  up  to  60  /u.  diam.  Florida,  Cal. 

So.  America,  Europe. 

Though  this  plant  has  long  been  kept  as  a  distinct  genus,  its 
inclusion  in  Spirogyra  seems  justified  by  an  intermediate  form, 
Sirogonium  ceylanicum  Wittr.  It  is  amply  distinct  from  any 
other  American  species  by  the  combination  of  characters,  linear 
slightly  spiral  chromatophores  and  conjugation  without  forma- 
tion of  tubes. 

Doubtful  species  of  Spirogyra. 

S.  negleda  Wolle,  1887,  p.  216. 

5.  subaequa  Wolle,  1887,  p.  217;  appears  to  belong  under 
6*.  bellis. 

S.  rivularis  Wolle,  1887,  p.  220;  the  figures  in  PI.  CXXXVI 
do  not  agree  with  the  descriptions  of  other  authors. 

S.  adnata  Wolle,  1887,  p.  220,  PI.  CXXXV,  figs.  3  and  4, 
seems  indistinguishable  from  5*.  dedmina. 

S.  elongata  Wolle,  1887,  p.  221,  refers  to  PI.  CXXXV,  figs, 
i  and  2,  but  in  the  volume  of  plates  these  figures  are  indicated 
as  5.  insignis  var.  elongata  ;  the  dimensions  of  the  figures  agree 
best  with  5.  elongata,  but  under  the  circumstances  it  is  uncer- 
tain just  what  Wolle's  plant  was.  5.  elongata  Wood,  1872,  p. 
164,  PI.  XIV,  fig.  i  is  5".  tcnidssima  (Hass.)  Kiitz. 

3.     DEBARYA  Wittrock,  1872,  p.  35. 

Cells  cylindrical,  about  5  times  as  long  as  broad;  dissepi- 
ments even  ;  chromatophore  an  axillary  plate  with  several  pyre- 
noids ;  conjugation  between  two  filaments  not  differing  in 


120          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

appearance;  zygospore  formed  in  the  tube,  with  smooth,  sac- 
cate, yellowish,  translucent  outer  membrane,  and  browish-yellow 
median  membrane,  with  three  longitudinal  parallel  ridges,  con- 
nected by  fine,  radial  cross  lines. 

D.  GLYPTOSPERMA  (De  Bary)  Wittrock,  1872,  p.  35;  P. 
B.-A.,  No.  1419.  Mougeotia  glyptosperma  De  Bary,  1858,  p.  78, 
PI.  VIII,  figs.  20-25;  Wolle,  1887,  p.  229,  PI.  CXLVI,  figs. 
6-9.  Filaments  crisped,  lubricous,  10-15  f-  diam.;  cells  6-12 
diam.  long  ;  fertile  cells  still  longer  ;  spores  ovoid,  42-49  X  30-40 
p..  Fig.  9.  Mass.,  Minn.,  Florida.  Europe,  New  Zealand. 

The  peculiarly  striate  spores,  ovoid,  set  lengthwise  of  the 
tube,  occupying  the  whole  space  between  the  filaments,  dis- 
tinctly characterize  this  species. 

4.     ZYGOGONIUM  Kiitzing,  1843,  p.  280. 

Cells  cylindrical,  as  long  as  broad  to  twice  as  long ;  dissepi- 
ments even  ;  two  axillary,  irregular  chromatophores,  each  with 
one  pyrenoid  ;  zygospore  formed  in  the  tube  between  two  cells 
not  differing  in  appearance ;  the  prolongation  from  each  cell 
cut  off  from  the  rest  of  the  cell  by  a  wall,  before  uniting  with 
the  prolongation  from  the  other  cell  ;  akinetes  sometimes 
formed,  as  in  Zygnema. 

The  protoplasm  that  is  to  take  part  in  the  formation  of  the 
zygospore  gathers  at  the  newly  formed  tube,  and  is  cut  off  from 
the  mother  cell ;  then  the  wall  at  the  end  of  the  tube  is  dissolved 
where  it  touches  the  tube  from  the  other  cell,  and  the  two 
recently  formed  small  cells  unite  to  form  the  spore.  In  Zygnema 
the  spore  is  formed  in  a  tube  which  still  communicates  with 
both  the  filament  cells.  This  is  practically  the  only  difference 
between  the  genera,  though  the  chromatophore  is  less  regularly 
star-shaped  in  Zygogonium  than  in  Zygnema. 

Z.  ERICETORUM  Kiitzing,  1845,  p.  224;  Z.  Agardhii  Wolle, 
1887,  p.  226,  PI.  CXLV,  figs.  6  and  7.  Filaments  15-25  p. 
diam.,  cells  1-4  diam.  long,  greenish,  becoming  brownish,  pur- 
plish, or  blackish  by  exposure  to  air  and  sun  ;  spores  globose  to 
ovoid,  20-25  P-  diam.  Fig.  10. 

Var.  TERRESTRE  Wittr.  and  Nordst.,  Alg.  Exsicc.,  No. 
1594  ;  P.  B.-A.,  No.  519.  Color  more  uniformly  purple  or 
violet ;  cells  somewhat  constricted  at  the  nodes ;  often  with 
short  rhizoidal  branches ;  wall  thicker  and  stouter ;  seldom 
fruiting.  On  moist  ground.  Both  type  and  variety,  Maine, 
Mass.,  Florida.  Europe,  So.  America. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  121 

The  peculiar  mode  of  producing  the  zygospores  places  this 
species  in  a  separate  genus  from  forms  like  Zygnema  pectinatum, 
which  it  otherwise  much  resembles.  Zygncma  Ralfsii  Wolle, 
1887,  p.  227,  appears  to  be  a  doubtful  determination,  and  the 
specimens  on  which  it  is  based  might  prove  to  belong  to  this 
species.  Of  Z.  aequale  Wolle  says  "we  assume  the  name  at  a 
hazard  "  ;  and  of  Z.  parvulum  "  we  quote  it  without  confidence 
in  its  value  "  ;  these  names  need  hardly  be  retained.  Z.  pur- 
purcum  Wolle,  1887,  p.  224,  is  very  incompletely  described  ; 
neither  from  text  or  plate  can  be  learned  the  form  of  the  chroma- 
tophores,  nor  the  character  of  the  membrane ;  dimensions  also 
are  uncertain,  and  until  further  evidence  it  must  be  classed  as 
doubtful. 

Family  2.     MESOCARPACEAE. 

Cells  cylindrical,  always  several  times  as  long  as  broad, 
united  in  unbranched  filaments,  rarely  having  short,  rhizoidal 
branches.  Chomatophore  an  axile  plate  with  several  pyrenoids  ; 
nucleus  at  the  middle  of  the  plate.  Conjugation  between  either 
two  cells  of  the  same  filament  or  cells  of  two  filaments.  Part  of 
the  protoplasm  separates  from  the  rest  in  the  cell ;  the  part  so 
separating  unites  with  a  similar  part  from  the  other  cell,  to 
form  the  zygospore,  which  is  either  entirely  in  the  tube  con- 
necting the  cells,  or  extends  somewhat  into  one  or  both  cells  ; 
spore  varying  in  form,  but  usually  lentiform,  with  round  or 
four-  or  six-angled  outline  ;  outer  membrane  of  spore  colored 
yejlow  or  brown,  smooth  or  variously  sculptured.  Partheno- 
spores,  akinetes,  and  aplanospores  sometimes  occur,  much  as  in 
the  Zygnemaceae. 

Only-two  genera  of  Mesocarpaceae  are  now  recognized,  Gona- 
toncma  with  two  species,  and  the  large  genus  Mougeotia,  includ- 
ing the  former  genera  Mesocarpus,  Crater  ospermum,  Plagiospcr- 
mitin,  Staurospermum  and  Sphaerospermum .  The  distinctions  as 
to  shape  and  surroundings  of  the  spore,  on  which  these  genera 
were  founded,  have  been  proved  to  be  uncertain,  the  types 
characteristic  of  the  different  genera  sometimes  occurring  on  the 

same  plant. 

KKY  TO  THE  GENERA  OF  MESOCARPACEAE. 

Aplanospores  with  double  membrane  formed  in  the  middle  part  of  a 
cell,  shutting  off  the  remainder  of  the  cell  by  a  wall.  Conjugation  un- 
known. 2.  GONATONEMA. 

Zygospores  formed  as  described  for  the  family ;  aplanospores  excep- 
tional, i.  MOUGEOTIA. 


122  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

i.  MOUGEOTIA  Agardh,  1824,  p.  XXVI. 
Cells  cylindrical,  several  times  as  long  as  broad  ;  dissepi- 
ments somewhat  lens-shaped  ;  chromatophore  an  axillary  plate 
with  two  or  more  pyrenoids;  zygospores  formed  in  the  tube, 
sometimes  occupying  the  whole  width  of  one  or  both  of  the  orig- 
inal cells,  thus  bounded  by  2,  3,  or  4  cells ;  spore  with  two 
membranes,  the  outer  colored,  smooth  or  sculptured  ;  akinetes, 
when  occurring,  with  single  membrane,  formed  by  a  division  of 
the  mother  cell  into  three  parts,  of  which  the  middle  part  be- 
comes the  akinete. 

KEY  TO  THE  SPECIES  OF  MOUGEOTIA. 

i.     Fertile  cell  bounded  by  2  cells.     Sect.  MESOCARPICAE  2. 

i.     Fertile  cell  bounded  by  3  cells.     Sect.  PI,AGIOSPERMICAE. 

14.     M.  tennis. 

i.     Fertile  Cell  bounded  normally  by  4  cells,  exceptionally  by  2  or  3. 
Sect.  STAUROSPERMICAE.  13. 

2.     Conjugation  scalariform.  3. 

2.     Conjugation  lateral,  rarely  scalariform.  12.     M.  genuflexa. 

2.     Conjugation  geniculate.  13.     M.  laetevircns. 

3.     Spore  smooth.  4. 

3.     Spore  pitted  or  punctate.  n. 

4.     Filaments  15  M  diam.  or  less.  3.     M.  parvula. 

4.     Filaments  20  M  diam.  or  more.  5. 

5.     Spore  diam.  greater  than  length  of  tube;  spore  extending  into  the 

cell  on  each  side.  6. 

5.     Spore  occupying  the  tube  only.  9. 

6.     Spore  60  /j.  diam.  5.     M.  minnesotensis. 

6.     Spore  45  /j.  diam.  or  less.  y. 

7.     Filaments  15  ^  diam.  or  less.  7.     M.  delicatula. 

7.     Filaments  20  fj.  diam.  or  more.  8. 

8.     Filaments  straight.  4.     M.  sphaerocarpa. 

8.     Filaments  geniculate.  6.     M.  divaricata. 

9.     Filaments  about  50  M  diam.  10.     M.  crassa. 

9.     Filaments  30  M  diam.  or  less.  10. 

10.     Spores  55-60  M  diam.  u.     M.  macrospora. 

10.     Spores  30-40  /JL  diam.  i.     M,  scalaris. 

n.     Spores  transversely  ovoid,  extending  into  the  filaments. 

8.  M.  verrucosa. 
ii.  Spores  globose  or  nearly  globose.  12. 

12.     Filaments  8-10  /JL,  rarely  15  M  diam.  2.     M,  nummnloides. 

12.  Filaments  25-32  /*  diam.  9.  M.  robusta. 

13.  Spores  punctate.  15.  M.  quadrangulata. 

13.  Spores  smooth.  !4. 

14.     Filaments  bluish  or  purplish  with  age.  18.     M.  capucina. 

14.     Filaments  not  bluish  or  purplish  with  age.  15. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  123 

15.     Filaments  10-12  n  diam.  19.     M.  calcarea. 

15.     Filaments  8  /x  or  less.  16. 

16.     Spores  quadrangular  with  concave  sides.  16.     M.  viridis. 

16.     Spores  quadrangular  with  straight  sides.  17.     M.  elegantula. 

1.  M.   SCALARIS  Hassall,   1842,  p.  45;  P.  B.-A.,  No.  963  ; 
Mesocarpus  scalaris  Wolle,    1887,   p.   230,   PL  CXI/VII,  figs.  2 
and  3  ;  Sphacrocarpus  scalaris  Kiitzing,  18553,  p.  2,  PI.  V,  fig.  i. 
Filaments  25-30  /tx  diam.,  rarely  20-23  /x»  cells  2-6  diam.  long, 
rarely  more ;    fertile  cells  somewhat  elongate,  slightly  genicu- 
late  ;  spores  30-38  /x  diam.,  globose  or  slightly  ovoid,  membrane 
yellowish  brown,  smooth,  occupying  the  tube  between  the  two 
straight  or  very  slightly  bent  cells.*     Mass.,  N.  J.  Europe. 

2.  M.    NUMMULOIDES    (Hass.)    De   Toni,     1889,    p.     713; 
P.  B.-A.,  No.  714;  Mesocarpus  nummuloides  De  Bary,  1858,  p. 
80,  PI.  VIII,  figs.  9  and  10;  Wolle,  1887,  p.  231,  PI.  CXLVIII, 
figs,  i  and  2.   Filaments  8-10 /x,  rarely  15 /x  diam.,  cells  5-12  diam. 
long;    spores  globose  or  broadly  ovoid,    17-23  /x  diam.,    rarely 
larger,  occupying  the  tube  but  not  extending  into  the  filaments  ; 
membrane  brown,  pitted.     Me.,  Mass.,  N.  J.  Europe. 

3.  M.  PARVULA  Hassall,  i843b,  p.  434;  Mesocarpus parvulus 
DeBary,  1858,  p.   80,   PI.   II,  fig.    15;  Wolle,  1887,  p.  230,  PI. 
CXLVIII,  figs.  3  &  4.     Filaments  6-10 /x  diam.,  cells  5- 1 2  diam. 
long;  spores  globose,    8-24  /x  diam.,   occupying  the  tube  and 
sometimes  projecting  very  slightly  into  the  filaments ;  membrane 
brown,  smooth. f     "  Pools,  north,  south  and  west."     Wolle. 

Europe. 

4.  M.    SPHAEROCARPA     Wolle,     1887,    p.     227,     PI.     CXLVI, 

figs,    i   and   2;   P.  B.-A.,   No.  1173.     Filaments  20-25 /x  diam., 
cells   3-6    diam.    long;    spores    spherical,   about   40  /x   diam., 

*  M.  recurva  (Hass.)  De  Toni,  1889,  p.  714;  Mesocarpus  recurvus  Wolle, 
1887,  p.  231,  PL  CXLVII,  fig.  6,  if  the  plate  is  correctly  drawn,  would 
seem  to  be  a  smaller  M.  scalaris,  or  a  larger  M.  parvula  Hass.,  and 
hardly  an  autonomous  species. 

M.  radicans  Wolle,  1887,  p.  231,  PI.  CXL/VIII,  figs.  7-10,  can  hardly  be 
M.  radicans  Kiitz.,  18553,  p.  i,  PI.  Ill,  fig.  I,  which  has  rhizoidal 
branches  smaller  than  the  filaments,  while  Wolle's  figures  show  branches 
as  large  as  the  filaments  and  of  the  same  appearance.  An  examination 
of  au  authentic  specimen  shows  the  figures  to  be  correct,  although  the 
branching  is  not  as  abundant  as  represented.  Possibly,  as  suggested  by 
Wolle,  it  is  an  abnormal  condition  of  M.  scalaris. 

t  M.  parvula  var.  angusta  (Hass.)  Kirchner.  Under  this  name  is  dis- 
tributed in  Tilden,  Amer.  Algae,  No.  284,  a  sterile  plant,  grown  in  an 
aquarium  under  abnormal  conditions  ;  it  can  hardly  be  considered  a  cer- 
tain determination. 


124          TUFTS  .COLLEGE  STUDIES,  VOL.  II,  No.  3 

smooth,  projecting  from  the  tube  into  the  conjugating  cells.* 
N.J.,  Pa.,  Florida,  Cal. 

5.  M.    MINNESOTENSIS   Wolle,    1887,   p.  228,  PI.  CXLVI, 
fig.  3.     Filaments  15-18  p.  diam.,  cells  4-5  diam.  long;  spores 
spherical,  reddish  brown,  about  60  p.  diam.,   projecting  much 
into  the  conjugating  cells.     Minn. 

6.  M.  DIVARICATA  Wolle,  1887,  p.  228,  PI.  CXLVI,  fig.  4. 
Filaments  20  ti  diam.,  cells  4-10  diam.  long,  fertile  cells  some- 
what geniculate  ;  spores  about  45  p.  diam.,  brown,  projecting  into 
the  conjugating  cells.     Pa. 

7.  M.  DELICATULA  Wolle,  1887,  p.  228,  PI.  CXLVI,  fig.  5. 
Filaments  12-14  M  diam..  cells  4-6  diam.  long;  spores  spherical, 
25-30  /u,   diam.,  .projecting  slightly  into   the  conjugating  cells. 
Canada. 

The  four  species  last  named  have  the  character  in  common 
of  large  spores  occupying  not  only  the  whole  length  of  the  tube, 
but  also  part  of  each  of  the  conjugating  cells.  M.  sphaerocarpa 
has  been  found  in  California,  agreeing  well  with  Wolle's  de- 
scription and  figure  ;  the  three  others  are  known  only  by  Wolle's 
descriptions  ;  if  his  figures  are  correct,  it  would  seem  difficult  to 
place  them  under  species  before  described,  and  they  differ 
too  much  to  be  consolidated  in  one  species ;  there  seems 
to  be  no  better  way  than  to  copy  the  descriptions  and  await 
developments. 

8.  M.  VERRUCOSA  Wolle,  1887,  p.  229,  PI.  CXLVIII,  fig.  5. 
Filaments  13-14  p-  diam.,  cells  6-10  diam.  long,  somewhat  genic- 
ulate ;  spores  transversely  ovoid,  projecting  into  the  conjugating 
cells,  about  40X20-25  /A;  membrane  brown,  coarsely  granular. 
Alabama. 

An  imperfectly  known  plant,  no  sterile  filaments  having  been 
recorded  ;  but  the  characters  seem  to  make  it  a  distinct  species  ; 
unless  indeed  it  might  be  an  ill-preserved  and .  inaccurately 
figured  Debarya  glyptosperma. 

9.  M.  ROBUSTA   (De  Bary)   Wittrock  in  Wittr.  &  Nordst., 
Alg.   Exsicc.,  No.  651  ;  Mesocarpus  robustus  De  Bary,  1858,  p. 
80,   PI.  II,  fig.   16;  Wolle,    1887,  p.  231,  PI.  CXLVII,  fig.  5. 

*  M.  levis  (Kiitz.)  Archer,  1867,  PI.  VIII,  figs.  1-3,  is  near  M.  sphacro- 
carpa,  but  has  shorter  cells  and  spores  of  about  the  same  diameter  as  the 
filaments,  but  considerably  longer,  and  set  at  right  angles  to  the  fila- 
ments. There  is  a  somewhat  doubtful  report  of  its  occurrence  in  the 
West  Indies. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  125 

Filaments  25-32  /j.  diam.,  cells  3-8  diam.  long,  fertile  cells 
slightly  bent;  spores  globose-ovoid,  40-50  /x  diam.,  finely  punc- 
tate, occupying  the  whole  tube,  but  not  projecting  into  the  fila- 
ments ;  membrane  reddish-brown.  Mass.,  N.  J.  Europe. 
The  plant  figured  by  Wolle  has  spores  more  nearly  globose 
than  the  usual  Kuropean  form. 

10.  M.  CRASSA  (Wolle)  De  Toni,    1889,  p.  716;  Mesocarpus 
crassus  Wolle,    1887,   p.   230,   PI.  CXLVII,  fig.   r.     Filaments 
about    50  /u,  diam.,    cells   4-10   diam.    long;    spores   spherical, 
smooth,  about  65  //,  diam.,  entirely  filling  the  tube,  but  not  ex- 
tending into  the  filaments.     Florida. 

11.  M.  MACROSPORA  (Wolle)  De  Toni,  1889,  p.  716;  Mcso- 
carpns  macrosporus  Wolle,    1887,   p.   230,   PI.   CXLVII,   fig.    4; 

•  P.  B.-A.,  No.  1368.  Filaments  about  30  p.  diam.,  cells  6-10 
diam.  long;  fertile  cells  distinctly  geniculate  ;  spores  55-60  p. 
diam.,  occupying  full}'  the  tube,  but  not  projecting  into  the  fila- 
ments, spherical,  smooth.  N.  H.,  Pa. 

12.  M.  GENUFLEXA  (Dillw.)  Agardh,  1824,  p.  83;  P.  B.-A., 
No.  312  ;  Mesocarpns plcurocarpus  De  Bary,  1858,  p.  81,  PI.  Ill, 
fig.  14;  Plcurocarpus  nu'rabilis  Wolle,  1887,  p.  232,  PI.  CXLIX, 
figs.    8-15.     Filaments    25-33   /u.   diam.,    cells    2-5    diam.    long, 
straight  or  geniculate,  in  the  latter  case  often  uniting  with  other 
filaments,  but  not  producing  fruit  in  this  way  ;  spores  globose 
or  ovoid,  smooth,  yellowish-brown,   usually  formed  by   lateral 
conjugation,  over  the  dissepiment  between  the  two  conjugating 
cells.     N.  Y.,  Mass.,  Me.,  N.  J.  Europe. 

A  common  species,  forming  great  expansions  in  quiet  water, 
pale  yellowish  or  whitish  green  ;  when  removed  from  the  water 
the  filaments  soon  tend  to  break  up  into  the  individual  cells. 
Though  the  species  is  common  almost  everywhere,  the  fruit  has 
been  considered  rather  rare  ;  but  when  it  does  occur  the  whole 
mass,  110  matter  how  extensive,  is  usually  all  in  fruit  at  once. 
The  scalariform  conjugation  is  very  rare,  but  has  been  observed 
in  this  country.* 

13.  M.    LAETEVIRENS    (A.    Br.)    Wittrock    in    Wittr.    and 
Nordst.,  Alg.,   Exsicc.,   No.  58;   Craterospermum  laetevircns  De 
Bary,   1858,  p.  81,  PI.  Ill,  figs.  1-13;  Wolle,  1887,  p.  235,  PI. 

*  Pleurocarpus  columbianus  Wolle,  1887,  p.  232,  PI.  CXLIX.  figs.  6 
and  7,  is  described  with  filaments  considerably  larger  than  in  M.  genit- 
flexa ;  fruit  is  unknown;  it  is  probably  only  a  form  of  the  common 
species.  The  examination  of  a  specimen  from  Bethlehem,  Pa.,  marked 
Pleurocarpus  columbianus  in  Wolle's  writing,  shows  filaments  from 
30  to  35  n  diam.  ;  but  little  more  than  in  M.  genuflexa. 


126    TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

CL,,  figs,  ii  and  12;  P.  B.-A.,  No.  1367.  Filaments  22-40  /x 
diam.,  cells  3-8  diam.  long;  conjugation  geniculate ;  spores 
short  cylindrical,  with  the  ends  towards  the  filaments,  about  40 /u, 
long  by  45-60  ti  diam.;  projecting  slightly  into  the  filaments; 
membrane  yellow-brown,  smooth.  N.  H.,  Mass.  Eiirope. 

Wolle's  notes  on  localities  for  this  species  are  somewhat  con- 
tradictory ;  after  "Frequent  in  pond  near  Worcester,  Mass." 
he  adds  "The  only  specimens  recognized  as  possibly  of  this 
genus  were  collected,  July,  1880,  in  Green  Pond,  New  Jersey." 

14.  M.  TENUIS  (Cleve)   Wittrock,    1872,  p.   39;  Plagiosper- 
mum  tenue  Cleve,  1868,  p.  35,  PI.  X,  figs.  6  and  7.     Filaments 
10-13  /xdiam.,  cells  8-16   diam.   long;  one  of  the   conjugating 
cells  dividing  into  three,  the  lateral  cells  remaining  sterile  while 
the  spore  is  formed  in  the  central  cell,  the  other  conjugating 
cell  being  then  separated  from  it  by  a  wall,  so  that  the  fertile 
cell  is  bounded  by  three  cells,  two  in  the  same  and  one  in  the 
other  filament.     Pa.,  Florida,  N.  J.  Europe. 

Wolle  describes  his  plant  as  var.  minor,  cells  17-18  \i  diam., 
and  refers  to  Cleve's  description  as  giving  measurements  25-30 
/u,  diam.;  evidently  an  error.  As  Wolle's  plant  is  larger  than 
Cleve's  there  is  no  need  for  preserving  the  varietal  name. 

15.  M.  QUADRANGULATA  Hassall,  i843b,  p.  434  ;  M.  quadrata 
Wittr.    and    Nordst.,    Alg.,    Exsicc.,    No.  61  ;    Staurospermum 
quadratum  De  Bary,  1858,  p.  81,  PI.  VIII,  fig.  n  ;  Wolle,  1887, 
p.   234,    PI.   CL,   figs.  6-8.     Filaments  8-12  p.  diam.,  cells  6-12 
diam.  long,  fertile  geniculate  ;  spores  quadrangular  with  trun- 
cate or  incurved  angles  in  front  view,  i.e.  when  placed  so  that 
the  two  filaments  are  in  a  plane  at  right  angles  to  the  line  of 
vision  ;  elliptic  in  form  in  side  view ;  occupying  the  width  of 
both    filaments;    membrane    uncolored,    pitted.     Mass.,    N.  J. 
South  Carolina.  Europe. 

16.  M.  VIRIDIS  (Kiitz.)  Wittrock,    1872,  p.   39  ;   Wittr.  and 
Nordst.,    Alg.    Bxsicc.,    No.    1591  ;    Staurospermum    viride   De 
Bary,  1858.  p.  81,   PI.   II,  figs.  17  and  18  ;   Wolle,  1887,  p.  234, 
PI.  CL,,  figs.  9  and  10.     Filaments  6-8  /x  diam.,  cells  4-10  diam. 
long  ;    spores  quadrangular,  with  concave  sides ;    in  side  view 
oblong  ;    occupying  the   width   of    both  filaments,  outer  mem- 
brane  colorless,    smooth,   depressed   at   the  corners.     Fig.    10. 
N.  J.,  Fla.  Europe. 

17.  M.  ELEGANTULA    Wittrock,    1872,    p.    40,    PI.    Ill,    figs. 
5-8;  G.   S.   West,    1905,   p.   284.     Filaments  4-5  //.  diam.,  cells 
15-30   diam.  long;    chromatophore  occupying  the   central   two 
thirds  of  the  cell,  with  5-8  pyrenoids  ;  conjugating  cells  genicu- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  127 

late;  spore  20-24 /a  long  and  wide,  12-14/11  thick,  in  face  view 
cruciform-quadrate,  in  side  view  subelliptic  with  truncate 
apices  ;  outer  membrane  smooth,  hyaline,  in  front  view  with 
slightly  rounded  angles,  in  side  view  oval.  W.  I.  Sweden. 

18.  M.   CAPUCINA  (Bory)   Agardh,    1824,  p.  84;    P.  B.-A., 
Nos.  563,  1420  ;  Staurospermum  capudnum  De  Bary,  1858,  p.  81  ; 
Wolle,  1887,  p.  234,  PI.  CL,  figs.  1-5.     Filaments  15-20  p.  diam.,' 
cells  6-14  diam.  long,  fertile  cells  sometimes  shortened;  spores 
dark  red  to  ochre  color,  cruciate  to  quadrangular  with  much 
concaved  sides ;  seen  from  the  edge,  linear  oblong ;  occupying 
the  width  of  both  filaments;  membrane  smooth.     Mass.,  N.  J. 

Europe. 

Forming  masses  which  except  when  quite  young  have  a  color 
ranging  from  bluish  to  deep  violet. 

19.  M.  CALCAREA   (Cleve)   Wittrock,    1872,  p.  40,   PI.  II. 
Filaments  10-14  ^diam.,  cells  4-20  diam.  long;  slightly  genic- 
ulate    in    conjugation ;    spores   varying    in    form,    mostly   glo- 
bose or  angular-globose,  21-50,  usually  30  p.  diam.;  membrane 
brown,  smooth.     Greenland.  Europe. 

It  was  in  this  species  that  the  different  modes  of  spore  forma- 
tion, supposed  to  distinguish  different  genera,  were  first  ob- 
served occurring  on  one  individual. 

2.     GONATONEMA  Wittrock,  1878,  p.  9. 

Vegetative  cells  as  in  Mougeotia ;  conjugation  unknown; 
aplanospore  with  double  membrane  formed  in  the  middle  of  an 
elongated  cell,  the  portions  each  side  of  the  spore  being  shut  off 
by  the  formation  of  cross  walls. 

G.  VENTRICOSUM  Wittrock,  1878,  p.  16,  figs.  1-13;  Wolle, 
1887,  p.  233,  PI.  CXLIX,  figs.  1-5;  Wittr.  and  Nordst.,  Alg. 
Exsicc.,  No.  652;  G.  notabile,  P.  B.-A.,  No.  1174.  Filaments 
5-7  p.  diam.,  somewhat  bent  geniculately,  cells  6-16  diam.  long ; 
spores  obliquely  elliptic,  one  side  being  more  convex  than  the 
other;  seen  from  the  side,  elliptic,  22-29X13-16^;  12-15/4 
thick,  yellowish,  smooth.  Fig.  u.  Pa.,  Cal.  Europe. 

Order  VOLVOCALES. 

Vegetative  cells  always  motile,  or  readily  passing  into  a  motile 
stage  as  vegetative  cells,  solitary  or  united  into  disk,  spherical, 
or  other  shape,  but  not  into  filaments.  Cells  uninucleate ; 
chromatophore  usually  cup-shaped. 

KEY  TO  THE  FAMILIES  OF  VOLVOCALES. 
i.    Cells  free,  never  forming  colonies.        i.     CHLAMYDOMONADACEAE. 


128  TUFTS  COLLEGE  STUDIES,  VOL,.  II,  No.  3 

i.  Cells  united  in  colonies.  2. 

2.  Colonies  of  various  form,  cells  motile  when  free,  sometimes  when 

in  colonies.  3.  TETRASPORACEAE. 

2.  Colonies  spherical,  ovoid,  or  disk-shape  ;  cells  normally  always 

motile.  2.    VOI/VOCACEAE. 

Family  i.  CHLAMYDOMONADACEAE. 
Cells  free,  globose,  ovoid,  fusiform,  or  subcylindrical,  rarely 
attached  by  gelatinous  threads,  with  2  or  4  cilia  ;  chromato- 
phore  thick,  cup-shaped,  sometimes  more  or  less  split,  with  or 
without  one  or  more  pyrenoids ;  asexual  reproduction  by  zo- 
ospores,  2-8  formed  in  a  vegetative  cell,  and  similar  to  it  in 
form  and  structure,  increasing  to  the  normal  size  after  leaving 
the  mother  cell ;  also  by  akinetes ;  sexual  reproduction  by 
gametes,  similar  to  the  zoospores,  but  usually  smaller,  some- 
times 64  in  a  cell,  in  some  cases  with  thick  membrane  ;  in  some 
cases  the  male  gametes  are  smaller  than  the  female  ;  by  the 
copulation  a  spherical  zygote  is  produced,  usually  red  in  color. 
When  germinating  it  becomes  green  and  produces  asexual 
zoospores,  in  the  same  way  as  do  the  vegetative  cells. 

KEY  TO  THE  GENERA  OK  CHLAMYDOMONADACEAE. 
i.     Cells  fusiform.  3.     CHLOROGONIUM. 

i.     Cells  spherical  to  ovoid.  2. 

2.     Protoplasmic  threads  passing  through  the  cell  wall. 

2.    HAEMATOCOCCUS. 

2.     No  protoplasmic  threads  in  cell  wall.  i.     CHLAMYDOMONAS. 

i.     CHLAMYDOMONAS  Ehrenberg,  1833,  p.  288. 

Cells  globose,  ovoid,  or  subcylindrical,  with  2-4  cilia  issuing 
from  the  same  point ;  cell  with  thin,  soft,  rather  close  coating  ; 
chromatophore  with  one  or  more  pyrenoids,  and  usually  a  red 
stigma  ;  asexual  reproduction  by  repeated  division,  usually 
succeeded  by  the  loss  of  cilia,  or  taking  place  during  a  Palm- 
ella-stage ;  sexual  reproduction  either  between  similar  gametes, 
or  between  male  and  female  aplanospores.  Fig.  13. 

Chlamydomonas  forms  are  undoubtedly  common  in  America, 
as  elsewhere,  but  little  is  really  known  as  to  their  identity  with 
European  species,  which  themselves  are  by  no  means  all  clearly 
established.  De  Toni,  1889,  gives  6  species  with  some  detail, 
and  10  "species  minus  notatae."  Wille,  1900,  notes  that  the 
genus  contains  about  6  species,  but  does  not  name  them  ;  1903, 
he  gives  26  accepted  and  23  doubtful  species,  of  which  very  few 
coincide  with  species  described  by  De  Toni.  Wolle,  1887, 
mentions  as  American,  three  species,  one  of  them  new.  Miss 


THE  GREEN  ALGAE  OP  NORTH  AMERICA  129 

Snow,  1903,  figures  three  forms  found  in  Lake  Erie  and  de- 
scribes them  all  as  new  species  ;  they  appear  to  be  nearly  re- 
lated to  three  European  species,  but  sufficiently  distinct  to  give 
them  at  least  a  prima  facie  right  to  a  place  here  ;  one  other 
form  found  in  America  appears  identical  with  a  described  Euro- 
pean species;  these  four,  with  the  arctic  "red  snow"  are  all 
that  can  safely  be  given  here.  As  it  is  more  than  probable  that 
these  are  only  a  small  portion  of  the  species  occurring  here,  no 
key  is  given. 

1.  C.  GRACILIS  Snow,    1903,    p.   374,    PI.    I,   fig.   I.     Cells 
cylindrical,  rarely  ovoid  or  spherical,  10-13  /"•  long,  5-6  p.  diam.; 
color  dull  green;  cilia  2,  about  \y?   times  as  long  as  the  cell; 
stigma  a  dull  red  disk,  about  equidistant  from  either  end  ;  pyre- 
noid  at  extreme  posterior  end.     Lake  Erie. 

Nearly  related  to  C,  angulosa  Dill. 

2.  C.  COMMUNIS  Snow,   1903,  p.  374,  PI.  I,  fig.  II.     Cells 
ovoid,  ellipsoid,  or  cylindrical,   10-13/1*  long,  6-8 /u,  diam.;  color 
light  yellowish  green  ;  stigma  inconspicuous,  near  anterior  end  ; 
cilia   2,  slightly   longer  than  the  cell;    pyrenoid   near  center; 
division  longitudinal.     Lake  Erie. 

Nearly  related  to  ^S".  Stcinii  Gorosch. 

3.  C.  GLOBOSA  Snow,   1903,  p.  375,  PI.  I,   fig.  III.     Cells 
spherical  or  slightly  ellipsoid,  5-8  p.  diam.,  cilirf2,  slightly  longer 
than  the  cell ;  chromatophore  much  thickened  at  posterior  end  ; 
stigma  small,  inconspicuous  ;  pulsating  vacuoles  at  anterior  end  ; 
pyrenoid  at  posterior  end.     Lake  Erie. 

Nearly  related  to  C.  Reinhardi  Dang. 

4.  C.  MUCICOLA  Schmidle,   1897,   p.    17,   PI.   II,  figs.  4-8; 
Wille,  1903,  p.  136,  PI.  IV,  fig.  6.     Cells  ovoid,  6-8  p.  long,  3-4  /u. 
diam.  ;    cilia  '2,    longer  than  the  cell ;    pulsating  , vacuoles   at 
anterior  end  ;  no  stigma  ;  pyrenoid  near  center  of  cell ;  division 
transverse.     Mass.  Europe. 

5.  C.  NIVALIS  (Bauer)  Wille,    1903,  p.    147,   PI.   Ill,   figs. 
44  and  45,  PI.  IV,  fig.  25.     Cell  ovoid,  26-36  X  14-20  /u.,  wall 
thickish,  uniform  or  thickened  at  the  posterior  end,  more  or  less 
distinctly  lamellate  ;  chromatophore  cup-shaped,  with  one  pyre- 
noid ;  usually  thoroughly  colored  by  haematochrome  ;  asexual 
reproduction  by  division  into  aplanospores  with  thick,  lamellate, 
smooth  wall ;  also  by  Palmella-stage  of  free,  spherical,  thick- 
walled  red  cells,  repeatedly  dividing ;  sexual  reproduction  im- 
perfectly known,  but   resulting  in  a  spherical  or  subspherical 
zygote,  20-34  P-  diam.,  with  red  contents  and  colorless  wall,  the 


130  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

outer  surface  covered  with  dome-shaped  prominences  with  hex- 
agonal base.     Fig.  13. 

The  "red   snow"    of    arctic   and   high   mountain   regions; 

usually  included  in  the  same  genus  with  Haematococcus  pluvi- 

alis,  often  in  the  same  species  ;   but  Wille,  1903,  seems  to  have 

determined  the  proper  position.     Greenland,  Alaska.       Europe. 

2.     HAEMATOCOCCUS  Agardh,  1828,  PI.  XXIV. 

Cells  similar  to  those  of  Chlamydomonas  but  having  in  the 
motile  stages  protoplasmic  threads  passing  through  the  coating 
from  the  central  mass  to  the  wall ;  coating  usually  quite  thick, 
often  different  in  form  from  the  cell  itself ;  cell  with  or  without 
red  stigma,  often  deep  red  in  color  ;  asexual  reproduction  by 
biciliate  zoospores  produced  few  in  a  cell ;  probable  sexual 
reproduction  by  smaller  biciliate  gametes,  produced  many  in  a 
cell ;  but  actual  conjugation  has  not  been  observed. 

H.  PLUVIALIS  Flotow,  1844,  p.  415,  PI.  XXIV,  XXV;  H. 
lacustris,  P.  B.-A.,  No.  114;  Sphaerella  lacustris  Hazen,  1899, 
p.  211.  Resting  cells  spherical,  8-80  p.  diam.,  deep  red,  with 
thick  wall;  dividing  into  4-16  biciliate  zoospores,  with  wide, 
hyaline  coating,  through  which  pas's  very  fine,  protoplasmic 
threads  ;  after  a  short  time  these  spores  come  to  rest,  and  divide 
like  the  parent  cell ;  this  may  continue  for  an  indefinite  number 
of  generations ;  or  at  any  time  the  cells  may  enter  into  a  long 
resting  stage ;  under  certain  circumstances  the  resting  spore 
may  divide  into  4-32  small,  narrowly  cylindrical  or  fusiform 
spores,  probably  gametes.  Fig.  14.  Me.  to  Texas  and  Nebraska, 
Cal.  Europe. 

Common  in  shallow,  easily  dried  up  pools  ;  forming  a  dull 
red  coating  on  the  bottom  and  any  contained  objects  ;  in  the 
active  state  the  cells  are  nearly  or  quite  green,  with  chroma  to- 
phore  covering  the  cell  wall,  and  several  pyrenoids. 

3.     CHLOROGONIUM  Ehrenberg,  1837,  p.  172, 

Cells  spindle-shaped,  with  two  cilia  at  the  forward  end ;  coat- 
ing very  thin  ;  cells  with  two  or  more  pyrenoids,  a  red  stigma, 
and  many  vacuoles.  Asexual  reproduction  by  division  into  4 
or  8  daughter  cells  ;  sexual  reproduction  by  zoogametes  formed 
1 6  or  32  in  a  cell,  by  successive  division  ;  copulation  taking 
place  between  gametes  of  the  same  or  different  sizes,  forming  a 
round  red  zygospore,  at  whose  germination  4  new  individuals 
are  produced',  at  first  red,  then  green.  Only  one  species. 

C.  EUCHLORUM  Ehrenberg,  1837,  p.  172  ;  Dangeard,  1888, 
p.  114,  PI.  XI,  figs.  5-13.  Cells  25-35  /"•  l°ng>  8  /u,  diam.,  with 
thin  wall  and  two  cilia.  In  quiet  w^ater,  aquaria,  etc.  Europe. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  131 

The  authority  for  the  occurrence  of  this  species  in  North 
America  is  Wille,  Natiirlichen  Pflanzenfamilien,  p.  40. 

Family  2.     VOLVOCACEAK. 

Motile,  biciliate  vegetative  cells  as  in  Chlamydomonadaceae, 
but  united  in  families  of  definite  form,  mostly  spherical  or  ovoid, 
continuing  motile.  Asexual  reproduction  by  the  formation  of 
daughter  cells,  similar  to  the  parent ;  sexual  reproduction  vary- 
ing much  in  the  different  genera,  from  union  of  similar  cells,  to 
fully  specialized  oogonia  and  antheridia.  Fresh  water  plants. 

KEY  TO  THE  GENERA  OF  VOI/VOCACEAE. 
i.     Cells  arranged  in  the  form  of  a  plate  with  cilia  on  one  face. 

i.     GONIUM. 
i.     Cells  arranged  in  spherical,  ellipsoidal,  or  flattened  colonies;  cilia 

not  confined  to  one  face.  3. 

2.     Colony  ellipsoidal  or  spherical,  cells  crowded   together,  conical, 

reaching  toward  the  center.  2.     PANDORINA. 

2.     Cells  not  crowded  nor  reaching  towards  the  center. of  the  colony. 

3- 

3.     Colony  ellipsoidal  or  flattened,  cells  uniform  in  size.  4. 

3.     Colony  spherical  or  sphaeroidal,  or  if  ellipsoidal,  with  small  vege- 
tative and  large  gonidial  cells.  5. 
4.     Colony  ellipsoidal  or  spherical,  poles  not  differentiated. 

5.     EUDORINA. 
4.     Colony  flattened,  horse-shoe-shape,  poles  differentiated. 

4.    PLATYDORINA. 

5.     Cells  not  connected  by  protoplasmic  processes  ;  of  two  sizes,  smaller 
vegetative  at  one  pole  and  larger  gonidial  at  the  other. 

3.    PI.EODORINA. 

5.     Cells  connected  by  protoplasmic  processes,  not  markedly  different. 

6.     VOLVOX. 

i.     GONIUM  Miiller,  1773,  p.  60. 

Colony  in  form  of  a  quadrangular  disk,  with  rounded 
angles,  composed  of  4-16  biciliate  cells  in  a  single  layer,  en- 
closed in  a  wide,  colorless,  gelatinous  coating,  the  cilia  all  on 
one  side  of  the  disk;  cells  globose,  or  polygonal  by  mutual 
pressure  ;  membrane  thin  ;  chromatophore  with  one  large  pyre- 
noid  and  red  stigma.  Asexual  reproduction  by  successive 
division  of  individual  cells  in  the  colony,  also  by  akinetes  ;  sex- 
ual reproduction  not  observed. 

KEY  TO  THE  SPECIES  OF  GONIUM. 

i.     Colony  4-celled.  T-     G.sociale. 

i.     Colony  i6-celled.  2-     G. perforate. 


132  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

1.  G.  SOCIALE  (Dujard.)  Warming,  1876,  p.  82;  Oltmanns, 
1904,    p.    150,  fig.  95,   2  ;   G.  tetras  Wittr.   and   Nordst.,   Alg. 
Exsicc.,   No.  50.      Colony  4-celled,    20-48  /j.  wide,   vegetative 
cells  oval,  9-20  X  5-14  M,  often  with  two  indentations  in  the 
outer  end,  cruciately  arranged  about  a  central,  quadrangular, 
open  space.     N.  H.,  Mass.  Europe. 

2.  G.  PECTORALE  Miiller,   1773,  p.  60;  Wolle,  1887,  p.  163, 
PI.  CLI,  figs.   15-18;    Phyk.    Univ.,   No.   287.     Colony  25-90^ 
wide,  composed  of  16  cells,  4  central  and  3  at  each  side;  cells 
5-15  yu.  diam.;    akinetes  spherical,  12-15  M  diam.,  producing  4 
biciliate  cells,   each  of  which  develops  to  the  normal  colony. 
Fig.  16.     Me.,  Mass.,  Conn.,  N.  J.,  Pa.,  N.  Y.,  Ont.,  111.,  Cal. 

Europe,  Asia,  Africa. 

In  the  fully  developed  i6-cell  colony,  there  is  a  quadrangular 
space  between  the  four  central  cells,  and  16  triangular  spaces 
among  the  surrounding  cells ;  at  the  four-celled  stage  of  devel- 
opment this  species  is  distinguished  from  G.  soiiale  by  having 
two  triangular  spaces,  while  G.  sotiale  has  a  quadrangular  cen- 
tral opening. 

2.     PANDORINA  Bory,  1824,  p.  600. 

Colony  globose  or  subglobose,  8,  16,  32  or  64  cells  forming 
a  botryoidal  mass,  surrounded  by  a  wide,  gelatinous  coating ; 
cells  with  close,  thin  membrane,  red  stigma,  and  two  cilia  ; 
chromatophore  with  one  pyrenoid.  Asexual  reproduction  by 
continued  division  of  the  cells  ;  sexual  reproduction  by  the  union 
of  similar  biciliate  gametes,  produced  singly  in  any  cell  of  the 
colony ;  by  the  union  of  two  such  gametes,  of  the  same  or  dif- 
ferent size,  a  zygote  is  produced,  of  reddish  color,  which  after  a 
period  of  rest  produces  1-3  large,  biciliate  red  zoospores  ;  these 
after  a  period  of  rest  produce  new  colonies  by  vegetative  divi- 
sion. 

P.  MORUM  (Mull.)  Bory,  1824,  p.  600;  Ehrenberg,  1838, 
p.  53,  PI.  II,  fig.  33  ;  Wolle,  1887,  p.  161,  PI.  CUII,  figs,  i-io  ; 
P.  B.-A.,  No.  1175.  Colony  globose  to  ellipsoid,  up  to  220 /u, 
broad,  usually  of  16  cells,  rarely  more  or  less;  cells  9-15  /u, 
diam.;  zygote  with  smooth  external  membrane.  Fig.  17.  Mass., 
Wis.,  111.,  Cal.  Europe,  Asia,  So.  America,  New  Zealand. 

3.     PLEODORINA  Shaw,  1894,  p.  279. 

Colony  spherical  or  ellipsoid,  containing  biciliate  cells 
arranged  in  a  single  layer  near  the  surface  of  the  colony  ;  cells 
of  two  kinds,  vegetative  cells  in  the  anterior  part  of  the  colony, 
gonidial  cells  in  the  posterior  part ;  cells  unconnected,  each  with 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  133 

a  red  stigma,  one  chrornatophore  occupying  nearly  the  whole 
cell,  with  one  to  many  pyrenoids  ;  gonidial  cells  developing 
asexually  to  form  new  colonies,  by  repeated  divisions ;  sexual 
reproduction  unknown. 

A  genus  comprising  two  species,  closely  related  to  Eudorina, 
and  until  sexual  reproduction  has  been  discovered,  there  must 
be  some  question  whether  it  is  not  a  stage  in  the  life  history  of 
the  older  genus. 

KEY  TO  THE  SPECIES  OF  PLEODORINA. 
i.     Gonidial  cells  2-3  times  larger  than  the  vegetative  cells,  of  about  the 

'same  number.  i.     P.  californica. 

i.     Gonidial  cells  somewhat  larger  than  the  four  vegetative  cells. 

2.     P.  illinoisensis. 

1.  P.  CALIFORNICA  Shaw,   1894,  P-  279>  PI-  XXVII.     Col- 
ony up  to  300  /j.  diam.,  containing  64  or  128  cells,  about  equally 
divided  between  vegetative  and  gonidial ;  gonidial  cells  about 
2-3  times  larger  diameter  than  vegetative  cells.     In  warm  shal- 
low fresh  water,  Cal.,  Ind.,  111.  Ceylon. 

2.  P.  ILLINOISENSIS   Kofoid,    1898,    p.   274,    PL   XXXVI, 
XXXVII.     Colony  46   X  38  --  200  X  175   M,    containing  32, 
rarely  16  or  64  cells ;  vegetative  cells  always  4 ;  gonidial  cells 
from  slightly  larger  to  twice  the  diam.  of  the  vegetative  cells. 
Fig.  18.     In  warm  shallow  water,  111.  Germany. 

The  ellipsoid  form  of  this  species,  with  the  4  vegetative  cells 
at  the  forward  end,  distinguishes  it  from  other  species  of  Volvo- 
caceae.  The  colony  moves  forwards  in  the  direction  of  the  long 
axis,  rotating  at  the  same  time  about  this  axis  ;  but  the  rota- 
tion is  not  uniform  in  direction,  changing  frequently,  like  the 
screw  of  a  steamer  when  the  engine  is  reversed  ;  the  movement 
of  the  colony  through  the  water  is  not  unlike  that  of  the 
steamer's  screw,  except  that  reversing  the  direction  of  revolu- 
tion has  no  effect  on  the  forward  motion,  which  goes  on  the 
same,  the  end  with  the  vegetative  cells  being  always  at  the 
front.  Another  differentiation  is  that  the  red  stigmata  in  the 
cells  are  brighter,  as  the  cells  are  located  nearer  to  the  forward 
end. 

4.     PLATYDORINA  Kofoid,  1899,  p.  419. 

Colony  much  flattened,  cells  in  one  layer,  but  alternately 
pointing  in  opposite  directions ;  cells  differently  arranged  in  the 
anterior  and  posterior  ends  ;  cells  all  similar,  biciliate,  with  red 


134          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

/ 

stigina,  parietal  chromatophore  and  one  pyrenoid  ;  asexual  re- 
production by  repeated  division  of  all  the  cells,  each  cell  thus 
forming  a  new  colony  ;  sexual  reproduction  unknown.  Only 
one  species. 

P.  CAUDATA  Kofoid,  1899,  p.  419,  PI.  XXXVIII.  Colony 
of  horse-shoe-shape  outline,  twisted  about  one-eighth  of  a  turn 
from  right  to  left;  maximum  size  165X145X25)11;  posterior 
end  with  3  or  5  prolongations,  or  tails,  from  the  common  sheath  ; 
cells  1 6  or  32,  arranged  in  a  marginal  row  of  10  or  12,  and  a 
central  area  of  6  or  20;  oblate  sphaeroidal,  15-20X15-18  p. 
Figs.  19  and  20.  . 

In  fresh  water,  111. 

The  alternating  position  of  the  cells,  the  cilia  from  one  pro- 
jecting on  the  opposite  side  of  the  colony  from  the  cilia  of  the 
next  cell,  seems  to  indicate  an  originally  rounded  colony,  com- 
pressed so  that  the  cells  from  opposite  sides  have  been  pushed 
in  between  each  other.  This,  with  the  peculiar  twist  to 
the  membrane,  strongly  separates  this  plant  from  all  hitherto 
known  forms.  It  is  noteworthy  that  the  twist  of  the  plane  is  in 
the  direction  corresponding  with  the  most  frequent  direction  of 
revolution  for  the  species. 

5.     EUDORINA  Ehrenberg,   1832,  p.  78. 

Colonies  globose  or  ovoid,  usually  composed  of  16-32-64  cells  ; 
cells  distributed  nearly  uniformly  through  the  peripheral  por- 
tion of  the  hyaline,  gelatinous  mass,  globose  or  subglobose, 
with  thin  membrane,  red  stigma,  and  one  or  more  pyrenoids  ; 
externally  produced  into  a  hyaline  pointed  projection  with  two 
cilia,  projecting  from  the  surface  of  the  colony.  Asexual 
reproduction  by  successive  division  of  cells,  ultimately  forming 
colonies  like  the  parent ;  sexual  reproduction  by  oogonia  and 
antheridia  borne  by  separate  individuals ;  all  the  vegetative 
cells  being  transformed  into  antheridia,  or  into  oogonia  ;  64 
fusiform  or  pyriform  antherozoids,  with  two  cilia,  formed  in 
each  antheridium ;  ripe  oospores  brownish,  with  smooth  ex- 
ternal membrane,  developing  into  new  colonies.  Only  one 
species. 

E.  ELEGANS  Ehrenberg,  1832,  p.  78,  PI.  II,  fig.  10  ;  Phyk. 
Univ.,  No.  231  ;  E.  stagnate  Wolle,  1887,  p.  160,  PI.  CLII,  figs. 
11-23.  Colonies  50-200 //.  diam.  ;  usually  of  32  cells,  arranged 
in  three  parallel  circles  of  8  each,  with  4  at  each  pole ;  cells 
12-24 /xdiam.  Fig.  21.  In  standing  water,  Pa.,  111.,  Wash. 

Europe,  So.  America,  New  Zealand^ 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  135 

6.     VOLVOX  Linnaeus,  1758,  p.  320. 

Colonies  spherical,  of  from  200-20,000  cells ;  cells  pyriform, 
united  by  protoplasmic  threads,  and  closely  set  near  the  surface 
of  the  sphere,  the  cilia  projecting.  A  small  number  of  cells, 
usually  8,  are  specialized  as  parthenogonidia,  asexually  form- 
ing new  colonies  by  repeated  division.  Sexual  reproduction  by 
antheridia  and  oogonia  ;  the  former  containing  8-256  clavate 
antherozoids,  with  red  stigma  and  two  cilia  ;  oospores  round, 
with  smooth  or  stellate  membrane ;  new  colonies  formed  by 
their  germination,  in  the  same  way  as  by  parthenogonidia. 

KEY  TO  THE  SPECIES  OF  Voi/vox. 
r.     Colonies  over  500  /u  diam.,  containing  several  thousand  cells. 

T.     V.  globator. 
i.     Colonies  not  over  300  /u.  diam.,  of  less  than  1,000  cells. 

2.     V.  aureus. 

1.  V.  GI.OBATOR  Linnaeus,  1758,  p.  320;  Ehrenberg,  1838,  p. 
68,  PI.  IV,  fig.  i  ;   Wolle,  1887,  p.  158,  PI.  CLI,  figs,  i-io,  CLII, 
figs.  1-9  ;   P.  B.-A,  No.  1264.     Colonies  monoecious  and  usually 
proteranclrous,  600-800  p.  diam.,  composed  of  many  cells,  3,000- 
20,000;  vegetative  cells  2-3  /*  diam.  ;    parthenogonidia   to   the 
number  of  8   formed  in  a  colony,  about  50  /u.  diam.  ;  oogonia 
20-40  in  a  colony,  about  50  p.  diam.  ;  oospores  brownish,  outer 
membrane  covered  with  stellate   projections,  inner   membrane 
thick,  gelatinous  ;  antheridia  seldom  over  5  in  a  colony,  globose, 
35-40  p.  diam.,  producing  numerous  antherozoids,   5-6  p.  long. 
Fig.  22.     Mass.,  Mich.,  111.,  Cal.  Japan,  Europe. 

One  of  the  most  striking  of  the  fresh  water  algae ;  the  very 
minute  cells  are  united  into  spherical  colonies,  large  enough  to 
be  visible  to  the  naked  eye,  and  moving  by  innumerable  vibra- 
tory cilia,  two  to  each  cell.  It  seems  to  be  generally  distrib- 
uted, and  sometimes  occurs  in  quantities  in  ditches  and  quiet 
pools,  and  is  found  practically  throughout  the  year. 

2.  V.  AUREUS  Ehrenberg,  1832,  p.  77;   1838,  p.  71,  PI.  IV, 
fig.  2;  P.  B.-A.,  No.  1176.     Proterogynous ;  colonies  about  200 
p.  diam.,   composed    of   600-900  cells;    vegetative   cells  4-6.5 //, 
diam.;  oogonia  1-15,  50-60  p.  diam.,   outer  membrane  smooth, 
oospore  reddish-brown,   4.8-60  //.  diam.  ;  antheridia   numerous, 
15-17   M   diam.,    containing    16    closely   packed    antherozoids, 
10-13X3-4 /*•     111.,  Mich.,  Cal.  Europe,  Asia. 

A  smaller  plant  than  V.  globator,  and  amply  distinct  in  every 
particular.  The  three  classes  of  reproductive  organs,  partheno- 
gonidia, oogonia,  and  antheridia,  may  occur  in  separate  colo- 


136  TUFTS  COLI/EGE  STUDIES,  VOL.  II,  No.  3 

nies,  or  any  two,  or  even  all  three,  may  occur  in  the  same 
colony,  but  in  varying  proportions ;  the  antheridia  may  dis- 
charge the  antherozoids  within  the  mother  colony,  or  may  escape 
intact,  and  discharge  their  contents  afterwards.  The  arrange- 
ment for  cross  fertilization  is  specially  noticeable ;  the  oogonia 
in  a  colony  ripening  before  the  antheridia  can  be  fertilized  only 
by  antherozoids  from  another  colony.  It  is  interesting  to 
observe,  here  in  what  was  a  debatable  land  between  animals 
and  plants,  as  efficient  arrangements  for  cross-fertilization  as  we 
find  among  flowering  plants. 

Family  3.     TETRASPORACEAE. 

Cells  normally  imbedded  in  gelatine,  in  structure  like  cells 
of  Chlamydomonas,  but  usually  without  cilia  ;  dividing  vegeta- 
tively  ;  asexual  reproduction  by  cells  assuming  2  or  4  cilia, 
escaping  from  the  gelatine,  and  after  a  relatively  long  free 
existence,  coming  to  rest,  and  producing  a  normal  colony 
directly  or  after  a  Palmella  stage ;  sexual  reproduction  by 
the  division  of  a  cell  into  several  zoogametes,  by  whose  copula- 
tion is  formed  a  zygote,  germinating  at  once  or  after  a  resting 
period. 

KEY  TO  THE  GENERA  OF  TETRASPORACEAE. 

i.     Cells  without  order  in  formless  gelatine.  i.     PALMELL'A. 

I.     Cells  and  colony  with  some  definite  form  and  arrangement.  2. 

2.     Cells  radiately  arranged»in  a  botryoidal  mass. 

2.     BOTRYOCOCCUS. 

2.     Cells  not  radiately  arranged.  , 

3.     Each  family  enclosed  in  a  tough,  elastic  membrane. 

3.     INEFFIGIATA. 

3.  Membrane,  if  any,  soft  and  delicate.  * 

4.  Cells  borne  on  filamentous,  branching  stalks.  c 

4.  Cells  without  definite  stalks.  „  6 

5.     Frond  soft  and  loose,  gelatine  not  very  conspicuous. 

7.    PRASINOCLADUS. 

5.     P'rond  firm,  at  first  solid,  later  hollow.  8.     COHINSIEI^A 

6.     Mature  frond  a  hollow  sac  of  definite  form.  7 

6.     Mature  frond  an  expanded  membrane  or  long  filament. 

4-    TETRASPORA. 

7.     Sac  solitary,  pyriform.  5.     APIOCYSTIS. 

7.     Sacs  subcylindrical,  united  at  base.  6.     PALMODACTYI.ON. 

i.     PALMELLA  ^lyyngbye,  1819,  p.  203. 

Cells  spherical,  with  bell-shaped  chromatophore  and  one  pyre- 
noid,  with  broad,  gelatinous,  diffluent  membrane;  asexual  re- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  137 

production  by  cell  division  in  all  directions,  cells  separating 
or  joined  in  small  families,  forming  irregular  gelatinous  masses  ; 
also  by  akinetes  and  by  ordinary  cells  developing  cilia  and  be- 
coming motile  ;  sexual  reproduction  by  biciliate  gametes. 

A  genus  in  which  have  been  included  at  various  times  a  mul- 
titude of  forms  which  had  no  character  in  common  but  that  of 
single  cells  contained  in  a  general  gelatinous  mass.  Many  of 
these  supposed  species  have  been  found  to  be  stages  of  growth 
of  Ulothrix,  Chaetophora  and  other  genera  ;  indeed  a  Palmella- 
stage  is  recognized  in  the  development  of  a  large  part  of  the 
green  algae.  Only  one  species  can  now  be  considered  as  a  dis- 
tinct organism  in  itself. 

P.  MINIATA  Leiblein,  1830,  p.  338;  Wolle,  1887,  p.  193,  PI. 
CLXII,  fig.  10 ;  Chodat,  1894,  p.  587,  PI.  XXII,  figs.  1-15. 
Cells  varying  much  in  size,  3-40  /u,  diam.,  colored  by  haemato- 
chrome,  orange-,  brick-,  or  blood-red,  or  yellow,  solitary  or 
united  2-8,  forming  irregular  gelatinous  masses;  membrane 
thick,  hyaline,  more  or  less  distinctly  lamellate,  diffluent ;  spor- 
angia 10-12  p.  diam.,  each  producing  4-8  zoospores  ;  or  a  single 
cell  developing  to  a  biciliate  zoospore-like  form  ;  sexual  repro- 
duction by  gametes  similar  to  the  smaller  zoospores.  In  moist 
places,  generally  distributed.  Fig.  23.  Europe. 

Var.  AEQUALIS  Nageli,  1848,  p.  67,  PI.  IV. D,  fig.  2  ;  Wolle, 
1887,  p.  193,  PI.  CLXII,  fig.  10 ;  P.  B.-A.,  No.  1314.  Cells  of 
nearly  uniform  size,  12-15  /"•  diam.;  color  brick-red,  easily 
changing  to  green  ;  wall  thinner  and  less  distinctly  lamellate 
than  in  the  type.  Cal.  Europe. 

2.  BOTRYOCOCCUS  Kiitzing,  1849,  p.  892. 
Cells  ovoid-cuneate  with  rounded  ends,  radiately  arranged  in 
rounded  colonies,  united  in  botryoidal  masses  by  a  gelatinous 
coating,  free  or  attached.  Chromatophore  covering  the  cell 
wall,  without  pyrenoid  ;  asexual  reproduction  by  cells  becom- 
ing biciliate  and  motile  ;  they  soon  come  to  rest,  divide,  and 
take  a  red  color;  in  these  cells  gametes  are  formed,  which  by 
conjugation  form  a  spherical  zygospore,  whose  further  develop- 
is  unknown. 

B.  BRAUNII  Kiitzing,  1849,  p.  892  ;  Wolle,  1887,  p.  195,  PI. 
CXXIV,  figs.  1-4;  P.  B.-A.,  Nos.  263,  1177.  Family  about 
i  mm.  diam.,  botryoidal  and  more  or  less  lobed,  at  first  green, 
later  brownish-red  ;  cells  ovoid  or  irregular,  about  6  /*  diam. 
Floating  in  stagnant  fresh  water.  Fig.  24.  Mass.,  N.  J.,  Cal. 

Europe. 


138          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

3.     INEFFIGIATA  W.  and  G.  S.  West,  1897,  p.  513. 

Cells,  ellipsoid  or  ovoid,  with  parietal  chromatophore  (and 
pyrenoid  ?)  often  colored  brick-red,  united  in  spherical  or  sub- 
spherical  families,  the  cells  superficial ;  each  family  surrounded 
by  a  tough,  elastic  membrane,  with  various  irregular  folds, 
lobes,  processes  and  spines,  the  older  membrane  often  including 
several  generations  of  families ;  asexual  reproduction  by  cell 
division,  the  families  separating  as  they  become  too  large. 

The  cells  have  considerable  resemblance  to  those  of  Botryo- 
coccus  Braunii ;  the  aggregations  are  more  complex,  the  outer 
membrane  seems  quite  distinct  from  anything  found  in  Botryo- 
coccus,  but  until  we  know  more  of  the  life  history  of  the  two 
forms,  their  distinctness  is  open  to  question. 

I.  NEGLECTA  W.  and  G.  S.  West,  1897,  P-  5°3  >'  I9°3,  P-  80, 
PI.  CCCCXI/VII,  figs.  1-6.  Cells  3-5X6-10  p.;  families  20-50  M 
diam.;  aggregations  of  successive  families  up  to  350  p..  In 
standing  water.  Fig.  25.  Me.,  Mass.  Europe. 

4.     TETRASPORA  Link,  1809,  p.  9. 

Colony  (frond)  gelatinous,  membranaceous ;  saccate,  tubular 
or  plane  ;  containing  globose  cells  in  a  single  layer,  scattered 
more  or  less  in  2s  and  43,  the  thick  cell  wall  diffluent  into  the 
general  membrane.  Asexual  reproduction  by  successive  divis- 
ion of  cells  in  the  plane  of  the  membrane  ;  also  by  cells  becoming 
ciliate  and  motile ;  they  later  come  to  rest,  lose  their  cilia,  form 
a  gelatinous  membrane,  and  divide  by  2s  and  43 ;  also  by  akin- 
etes.  Sexual  reproduction  by  the  conjugation  of  small,  biciliate 
gametes,  produced  8  in  a  cell,  the  zygospore  germinating  at 
once. 

A  genus  in  which  quite  a  number  of  species  have  been  de- 
scribed, some  of  them  not  very  sharply  distinguished.  They 
are  all  fresh  water  plants,  and  are  very  common  in  brooks  and 
pools. 

KEY  TO  THE  SPECIES  OF  TETRASPORA. 

I.     Frond  cylindrical  at  all  ages.  i.      T.  cylindrica. 

I.     Frond  cylindrical  only  when  young,  if  ever.  2. 

2.     Frond  an  irregularly  inflated  sac.  3.     T.  gelatinosa. 

2,     Frond  at  first  tubular,  but  soon  splitting  into  irregular  segments, 

often  much  perforate.  2.     T.  lubrica. 

i.     T.  CYLINDRICA  (Wahl.)  Agardh,  1824,  p.  188;  Kiitzing, 

i849a,  PI.  XXX  ;  Wolle,   1887,  p.   190,  PI.  CLXV,  figs.  7  and 

8;  P.  B.-A.,  Nos.  908,  1510.     Frond  attached,  up  to  one  meter 

long,  seldom  more,  up  to  2  cm.  diam.,  cylindrical,  unbranched, 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  139 

with  stipitate  base,  and  usually  somewhat  clavate  tip  ;  consist- 
ency firmer  than  in  other  species  of  the  genus;  cells  14-17 /x 
diam.,  with  thick  and  sharply  marked  wall,  generally  showing 
little  of  the  arrangement  in  fours.  Minn.,  Montana,  Alaska. 

l^n  rope. 

The  type  is  easily  recognizable  by  its  resemblance  in  habit 
and  texture  to  Enteromorpha  intestinalis ;  but  the  following 
variety  is  more  like  other  species  of  the  genus. 

Var.  extensa  (Tilden)  Collins,  nov.  comb.  ;  Tctraspora  extensa 
Tilden,  Amer.  Algae,  No.  48.  Fronds  very  long,  according  to 
the  author  up  to  35  meters,  narrow,  not  over  i  cm.  wide  ;  or 
irregularly  expanded  with  a  diameter  of  5  cm.;  gelatinous, 
bright  green  ;  cells  spherical,  more  or  less  in  groups  of  four, 
10-15 //.  diam.  IJ1  sluggishly  flowing  water,  in  tanks  of  State 
fish  hatcheries,  St.  Paul,  Minn. 

Much  more  gelatinous  than  the  type,  but  apparently  not  dis- 
tinct ;  probably  a  variety  due  to  local  conditions. 

2.  T.  LUBRICA  (Roth)  Agardh,   1824,  p.  188;  Wolle,  1887, 
p.  191,  PL  CLXV,  figs.  9-n  ;  P.  B.-A.,  Nos-  63,  861.     Frond 
at  first  attached,  tubular  or  saccate  ;  soon  splitting  and  forming 
irregular  expansions,  often  with  many  rounded  openings,  some- 
times quite  net-like  ;   up  to  20  cm.  long  and  wide,  very  gelatin- 
ous, usually  yellowish  in  color;    cells  7-11  p.  diam.,  generally 
in  fours.     Fig.  26.  Europe,  So.  America,  New  Zealand. 

Very  common  in  spring,  apparently  everywhere  throughout 
the  Northern  United  States  ;  the  perforated  and  net-like  form 
is  usually  known  as  var.  lacunosa  Chauvin,  but  really  has  no 
characters  by  which  it  can  be  distinguished  from  the  type. 

3.  T.  GELATINOSA  (Vauch.)  Desvaux,  1818,  p.  18  ;   Wolle, 
1887,  p.  191  ;   P.hyk.  Univ.,  No.  693  ;    Ulva gelatinosa  Vaucher, 
1803,  p.  244,  PI.  XVII,  fig.  2.     Forming  inflated  bullate  masses, 
not   lacunose  ;   very  soft  and  gelatinous;  cells  2.5-13  p.  diam., 
very  different  sizes  being  found  side  by  side  in  the  same  frond. 
Me.,  Mass.,  N.  J.,  Iowa,  Cal.  Europe. 

Generally  distributed  in  quiet  water  ;  the  fronds  are  more 
rounded  than  in  other  species,  and  the  lack  of  uniformity  in  the 
size  of  the  cells  is  marked.  But  there  are  intermediate  forms 
between  it  and  T.  lubrica* 

*T.  bullosa,  rioted  iu  practically  all  manuals  of  fresh  water  algae,  is  now 
pretty  well  known  to  be  a  Monostroma  ;  it  seems  to  be  not  uncommon 
in  Europe,  but  no  American  specimens  have  been  seen.  The  American 
specimens  passing  under  the  name  of  T.  bullosa  var.  cylindracea  (Hilse) 


140  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Forma  UNIFORMIS  Collins,  P.  B.-A.,  No.  1265.  Forming 
rounded,  gelatinous  masses  not  over  3  cm.  diam.;  cells  6-8  /x 
diam.,  varying  but  little  in  size.  Cal. 

5.  APIOCYSTIS  Nageli  in  Kiitzing,  1849,  p.  208. 
Colony  microscopic,  vesicular,  attached  by  a  stipe-like  base, 
containing  more  or  less  numerous  cells,  scattered  or  arranged  in 
circles,  the  thick  wall  diffluent  into  the  general  gelatinous  mass 
of  the  colony  ;  chromatophore  nearly  covering  the  cell  wall,  with 
one  pyreuoid  ;  cells  dividing  in  all  directions.  Asexual  repro- 
duction by  cells  becoming  biciliate  as  in  Tetraspora ;  sexual 
reproduction  by  the  union  of  smaller,  biciliate  gametes. 

A.  BRAUNIANA  Nageli,  1848,  p.  67,  PI.  II. A,  fig.  i  ;  Wolle, 
1887,  p.  202,  PI.  CXXIII,  figs.  6-10 ;  Wittr.  and  Nordst.,  Alg. 
Exsicc.,  No.  356.  Colony  pyriform,  pale  green,  20-100/1.  diam., 
about  twice  as  long  ;  containing  usually  8-32,  rarely  up  to  300 
globose  cells,  6-8  /x  diam.  Growing  on  various  algae  in  ponds 
and  ditches.*  Fig.  27.  Maine,  Mass.,  Fla. 

Eiiropc,  New  Zealand. 

6.     PALMODACTYLON  Nageli  in  Kiitzing,  1849,  p.  234. 
Colonies  microscopic,  unattached,  in  the  form  of  elongate  sacs, 
simple  or  branched,  often  radiating  from  a  common  center  ;  con- 
taining globose,  thick-walled  cells.     Asexual  reproduction    as 
in  Palmella. 

P.  VARIUM  Nageli,  1848,  p.  70,  PI.  II. B,  fig.  i  ;  Wolle,  1887, 
p.  189,  PI.  CXXIV,  figs.  8  and  9.  P.  simplex  Nageli,  1848,  p. 
70,  PI.  II. B,  fig.  2  ;  Wolle,  1887,  p.  189.  Colonies  composed  of 
many  simple  or  branched,  more  or  less  radiately  arranged  sacs, 
up  to  50  /A  diam.  by  280  p.  long  ;  cells  at  first  in  4-8  longitud- 
inal series,  later  crowded  and  without  order,  4-7  p.  diam.  Fig. 
28.  Maine.  Eiirope. 

P.  simplex  appears  to  be  merely  a  young  or  undeveloped 
state.  "  In  stagnant  fresh  water"  according  to  Wolle,  but  no 
definite  locality  given. 

Rabenhorst,  all,  as  far  as  seen,  appear  to  be  young  stages  of  T.  lubrica 
or  T.  gelatinosa.  The  plants  distributed  as  P.  B.-A.,  No.  64,  and  in  Til- 
den,  Ainer.  Algae,  No.  47,  seem  to  correspond  with  T.  gelatinosa  forma 
b.  of  Rabenhorst,  1868,  p.  40. 

T.  macrospora  F.  L.  Harvey,  1892,  p.  119,  PI.  CXXVI,  figs.  1-6,  should 
probably  be  included  under  T.  gelatinosa. 

*  A.  elongata  F.  L.  Harvey,  1892,  p.  120,  Pi.  CXXVI,  figs.  6-1 1,  from 
Maine,  differs  from  the  type  only  in  the  more  elongate  form  of  the  colony, 
and  the  slightly  larger  cells;  but  A.  Brauniana  varies  enough  to  in- 
clude the  form  and  sizes  given  for  A.  elongata. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  141 

7.  PRASINOCLADUS  Kuckuck,  1894,  p.  261. 
Plants  filamentous,  branching  above ;  filaments  formed  of 
compartments,  those  below  empty,  the  terminal  containing 
green  cells  ;  cells  with  band-shaped  chromatophore  and  red 
stigma.  Reproduction  by  cells  becoming  4-ciliate,  otherwise 
unchanged. 

P.  SUBSALSUS  B.  M.  Davis  in  P.  B.-A.,  No.  564;  Euglenop- 
sis  subsalsa  Davis,  1894,  p.  388,  PI.  XIX.  Filaments  monil- 
iform,  when  mature  about  %  mm.  long,  at  first  simple,  then 
di-tri-chotomously  branching  ;  cells  oblong,  12-20X6-9  p. ;  chro- 
matophore bright  green,  usually  extending  round  the  cell,  with 
no  pyrenoid  ;  compartments  of  filament  about  the  same  size  as 
the  cells,  separated  from  each  other  by  1-4  thin,  hyaline  cross- 
walls  ;  cilia  at  the  lower  end  of  the  motile  cells.  Forming  a 
thin  coating,  velvety  or  gelatinous,  on  pebbles,  Spartina,  etc.  ; 
salt  marshes  and  sheltered  rock  pools.  Fig.  29.  Mass.,  Me. 

Oltmanns,  1904,  p.  136,  proposes  the  family  Chlorodendraceae 
for  this  and  a  few  other  forms,  as  being  perhaps  the  nearest  rela- 
tives of  the  Flagellates  among  the  green  algae ;  but  while  the 
resemblance  is  striking,  the  line  of  connection  with  undoubted 
members  of  the  Tetrasporaceae  is  so  continuous,  from  Prasino- 
cladus  subsalsus  through  P.  lubricus  Kuckuck,  Ecballocystis  pul- 
vinata  Bohliu,  E.  japonica  Yendo,  and  Collinsiella  tuberculata 
Setchell  and  Gardner,  that  the  inclusion  of  all  these  forms  in 
the  Tetrasporaceae  seems  justified. 

8.     COLLINSIELLA  Setchell  and  Gardner,  1903,  p.  204. 

Frond  gelatinous,  solid  or  later  hollow,  composed  of  pyri- 
form  cells,  on  dichotomous,  gelatinous  stalks  tapering  down- 
ward from  the  cells ;  all  enclosed  in  the  general  gelatine. 
Chromatophore  band-shaped,  with  one  large  pyrenoid ;  zo- 
ospores  (?)  formed  from  the  contents  of  the  cells. 

C.  TUBERCULATA  Setchell  and  Gardner,  1903,  p.  204,  PI. 
XVII,  figs.  1-7;  P.  B.-A.,  No.  909;  Ecballocystis  Willeana 
Yendo,  1903,  p.  199,  PI.  VIII,  figs.  .1-15.  Frond  dark  green, 
firmly  gelatinous,  tuberculate ;  cells  12-20X9-12^;  cells  divid- 
ing, one  daughter  cell  remaining  in  position,  the  other  pushing 
on,  at  the  end  of  the  tapering  stalk;  this  division  many  times 
repeated  ;  lower  part  of  the  frond  attached  to  the  substratum  by 
filamentous  outgrowth  from  the  lower  cells.  Zoospores  (?)  8-16, 
or  sometimes  more,  in  the  cells  in  the  middle  and  upper  part 
of  the  frond.  Forming  minute  tubercles  on  stones  in  pools. 
Fig.  30. 

Vancouver  Isl.  to  Cal. 


142  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

The  description  given  is  made  by  combining  the  record  of 
Setchell  and  Gardner  with  that  of  Yendo.  The  arrangement  of 
the  cells  on  long,  dichotomous  stalks,  together  with  the  firm, 
solid  frond,  seem  to  justify  maintaining  Collinsiella  as  a  genus 
distinct  from  Ecballocystis.  The  transformation  of  vegetative 
into  motile  cells  has  not  been  observed  in  the  genus,  but  is  to 
be  expected,  as  in  other  respects  the  genus  resembles  Prasino- 
cladus. 

Order    PROTOCOCCALES. 

Vegetative  cells  motionless,  solitary  or  in  spherical  or  net-like 
combinations,  rarely  filiform.  Cells  uni-,  rarely  multi-nucleate  ; 
chromatophore  usually  single,  disk-  or  cup-shaped. 

KEY  TO  THE  FAMILIES  OK  PROTOCOCCALES. 

i.     Cells  free  or  united  in  gelatinous  colonies.  2. 

i.     Cells  united  in  regular,  net-  or  disk-shaped  colonies,  not  gelatinous. 

5.    HYDRODICTYACEAE. 
2.     Cells  inultinucleate,  relatively  large,  irregularly  branched. 

2.    PROTOSIPHONACEAE. 

2.     Cells  uninucleate,  of  definite  form.  3. 

3.     Cells  spherical,   relatively  large,  with   many  disk-shaped  chromato- 

phores.  3.    HAI/XSPHAERACEAE. 

3.     Cells  of  various  forms,  with  single  chromatophore.  4. 

4.     Cells  dividing  vegetatively.  4.     SCENEDESMACEAE. 

4.     Vegetative  cell-division  rare  and  abnormal. 

i.    PROTOCOCCACEAE. 
Family  i.     PROTOCOCCACEAE. 

Unicellular,  spherical  or  pyriform,  rarely  irregular;  free  or 
attached  ;  asexual  reproduction  by  zoospores  or  aplanospores  ; 
sexual  reproduction  by  zoogametes  in  some  instances ;  normal 
cell-division  rare  and  exceptional.  Marine  or  fresh  water. 

The  genus  Protococcns  formerly  contained  a  heterogeneous 
collection  of  unicellular  plants,  which  have  since  been  all  trans- 
ferred to  widely  separated  genera,  and  the  genus  is  now  hardly 
recognized  by  any  good  authority.  The  order  and  family  which 
derived  their  names  from  it  still  remain  in  good  repute.  P. 
ovalis  Hansgirg  in  Foslie,  1890,  p.  159,  PI.  Ill,  fig.  I2,  was 
founded  on  a  form  found  in  tide  pools  near  high  water  mark  in 
Norway,  and  the  same  form  has  been  found  in  a  similar  station 
in  Maine.  It  has  ovoid  or  ellipsoid  cells,  8-10X9-12  /A,  with 
thin  wall  and  yellow-green  contents,  solitary  or  congregated  in- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  143 

a  formless  mass.     Until  more  is  known  of  its  history,  it  cannot 
be  properly  located. 

KKV  TO  THE  GENERA  OF  PROTOCOCCACEAE. 

i.     Cells  attached  at  base  or  with  basal  prolongation.  2. 

i.     Cells  without  basal  attachment  or  prolongation.  3. 

2.     FYesh  water  ;  chromatophore  cup-shaped  ;  one  pyrenoid. 

6.     CHARACIUM. 

2.     Marine;  chromatophore  more  or  less  broken  ;  several  pyrenoids. 

7.    CODIOLUM. 

3.     Endophytic.  .  4. 

3.     Not  endophytic.  e;t 

4.     Color  more  or  less  deep  red.  4.     RHODOCHYTRIUM. 

4.     Color  green.  6. 

5.     Cell  membrane  with  spines,  ridges,  or  other  projections. 

2.    TROCHISCIA. 

5.     Cell  membrane  smooth.  i.     CHLOROCOCCUM. 

6.     Zoospores  and  gametes  biciliate.  3.     CHLOROCHYTRIUM. 

6.     Zoospores  4-ciliate ;  gametes  unknown.  5.     CHLOROCYSTIS. 

i.     CHLOROCOCCUM  Fries,  1825,  p.  356. 

Cells  spherical  with  usually  thin  membrane  ;  chromatophore 
covering  nearly  the  whole  cell  wall,  with  one  pyrenoid  ;  asexual 
reproduction  by  biciliate  zoospores,  produced  many  in  a  cell. 

The  species  of  this  genus  are  found  in  fresh  water,  and  more 
especially  in  wet  places  on  land,  often  where  there  are  impuri- 
ties from  sewage  or  other  animal  matter  that  would  be  fatal  to 
most  green  algae.  It  is  extremely  hard  to  draw  a  line  between 
Chlorococcum  and  Gloeocystis  on  the  one  hand  and  Zoochlorella  on 

the  other. 

KEY  TO  THE  SPECIES  OF  CHLOROCOCCUM. 

i.     Endozoic.         .  3.     C.  endozoicum. 

i.     Not  endozoic.  2. 

2.     Forming  thin  coatings  in  moist  places.  i.     C.  humicola. 

2.     Forming  gelatinous  submerged  masses.  2.     C.  infusionutn. 

1.  C.  HUMICOLA  (Nag.)  Rabenhorst,  1868,  p.  58  ;  P.  B.-A., 
No.  1066;   Cystococcus  humicola  Nageli,  1848,  p.  85,   PI.  III.K. 
Cells  varying  much  in  size,  3-25  p.  diam.,  spherical,  solitary  or 
united  by   2-4;    membrane  thin,   uniform,    hyaline.     Fig.   31. 
Greenland,  Mass.,  R.  I.  Europe. 

Forming  thin  green  coatings  in  moist  places,  especially  under 
dripping  water. 

2.  C.  INFUSIONUM  j^Schrank)   Meneghini,  1846,  p.   27,  PI. 
II,  fig.  3;  P.  B.-A.,  No.  1119.     Cells  spherical,  15-45 


144  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

rarely  larger ;  loosely  united  into  light  green,  gelatinous  masses  ; 
wall  sometimes  rather  thick,  hyaline,  more  or  less  distinctly 
lamellate.  Mass.  Europe. 

Forming  soft,  easily  scattered  gelatinous  masses  on  sub- 
merged objects. 

3.  C.  ENDOZOICUM  Collins,  P.  B.-A.,  No.  1323.     Cells  10-25 
/A  diam.,  spherical,  thin-walled.     In  the  mantle  of  the  mussel, 
Mytilus  edulis,  in  tide  pools.     Me. 

C.  natans  Snow,  1903,  p.  383,  PI.  Ill,  fig.  XI,  is  uncomfort- 
ably near  C.  infusionum,  none  of  the  characters  given  in  the 
description  being  distinctive. 

2.     TROCHISCIA  Kiitzing,  1845,  p.  129. 

Cells  globose  or  subglobose,  with  several  parietal  chromato- 
phores  and  one  or  more  pyrenoids,  with  thick  membrane, 
having  various  spines,  ridges,  or  other  projections  ;  asexual 
reproduction  rarely  by  cell  division,  more  commonly  by  aplano- 
spores,  formed  many  in  a  cell  by  repeated  division,  escaping  by 
dissolution  of  the  mother  cell  wall,  with  membrane  at  first 
smooth,  later  developing  characters  of  the  mother  cell. 

Some  of  the  species  of  Trochiscia  are  fresh  water  plankton 
algae,  some  inhabit  moist  places,  especially  dripping  rocks. 
Care  is  sometimes  needed  to  distinguish  them  from  spores  of 
desmids,  or  from  unicellular  stages  of  other  algae.  The  knowl- 
edge of  the  American  species  is  nearly  all  derived  from  the 
observations  of  Reinsch,  1886,  and  a  careful  comparison  of  his 
descriptions  and  figures  is  likely  to  leave  one  in  a  state  of  seri- 
ous doubt  as  to  the  validity  of  some  of  the  species ;  there 
are  certainly  three  types ;  respectively  with  warty  projections, 
spines,  and  wavy  ridges  ;  it  may  be  that  three  species,  one  of 
each  type,  would  include  all  our  forms. 

KEY  TO  THE  SPECIES  OF  TROCHISCIA. 
i.     Membrane  beset  with  papillae,  spines,  or  wart-like  prominences. 

2. 
i.     Membrane  beset  with  wavy  ridges.  5. 

2.     Projections  warty  and  irregular.  3. 

2.     Projections  spine-like.  4. 

3.     Projections  rather  distant,  bluntish  ;  cells  18-23  M  diam. 

i.     T.  granulata. 
3.     Projections  densely  set,  acutish  ;  cells  14-17  M  diam. 

2.     T.  aspera. 

4.  Spines  pyramidal,  of  unequal  length.       •  3.      T.  hirta. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  145 

4.  Spines  very  slender,  all  about  5  /j.  long.  4.  T.  aciculifera. 

5.  Ridges  intersecting,  enclosing  angular  areas.  5.  T.  relicularis. 

5.  Ridges  parallel  or  concentric.  6. 

6.     Membrane  one-sixth  cell  diain.  7.     T.  obtusa. 

6.     Membrane  one-third  cell  diam.  6.     T.  arguta. 

1.  T.    GRANULATA    (Reinsch)     Hansgirg,     1888,    p.    128; 
P.  B.-A.,  No.  761.     Acanthococcus  granulatus  Reinsch,  1886,  p. 
239,  PI.  XI,  figs.  3,  4,  and  7.     Cells  solitary  or  united  in  small 
families,  globose,  18-22  /A  diam.,  membrane  one-fifth  to  one-sixth 
cell  diam.,  covered  with  rather  distant,  bluntish,  warty  projec- 
tions.    Mass.  Europe,  So.  America. 

2.  T.  ASPERA  (Reinsch)  Hansgirg,   1888,  p.  128;  Acantho- 
coccus  asper  Reinsch,  1886,  p.   239,   PI.   XI,   fig.    2.     Cells  soli- 
tary, globose,  14-17  ^  diam.  ;  membrane  one-eighth  to  one-ninth 
cell  diam.,  densely  covered  with  somewhat  acute,  warty  projec- 
tions.    Dominica.  Etirope. 

3.  T.  HIRTA  (L,agerh.)   Hansgirg,    1888,   p.    128";  Acantho- 
coccus hirtus  Lagerheim,   1882,  p.  78,  PI.  Ill,  figs.  38  and  39; 
Wittr.  and  Nordst.,  Alg.  Exsicc.,  No.  446.     Cells  solitary  or 
united  in  small  families,  globose,  22-32  //,  diam.,  membrane  one- 
eighth  to  one-ninth  cell  diam.,  with  pyramidal  spines  of  unequal 
length,  one-fourth  to  one-fifth  the  cell  diam.     Fig.  32.     Green- 
land. Europe. 

4.  T.   ACICULIFERA    (Lagerh.)    Hansgirg,    1888,    p.    129; 
Acanthococcus  aciculiferus  Reinsch,  1886,  p.  241,  PI.  XI,   fig.  i. 
Cells  solitary  or  united  in  small  families,  globose,  subglobose  or 
ovoid,    15-30  //.   diam.  ;    densely   coated   with   very   numerous 
slender  spines,  up  to  5  /x,  long.     Mass.  Europe. 

5.  T.  RETICULARIS  (Reinsch)  Hansgirg,    1888,  p.    129;  P. 
B.-A.,  No.  1514;  Acanthococcus  reticularis  Reinsch,  1886,  p.  241, 
PI.  XI,  figs.  12  and  14  ;  including  T.  sporoides  (Reinsch)  Hans- 
girg, Acanthococcus  sporoides  Reinsch,  1886,  p.  242,  PI.  XII,  fig. 
24  ;  and  T.  Reinschii  Hansgirg,  Acanthococcus  sp.,  Reinsch,  1886, 
p.  242,  PI.  XI,  fig.   13.     Cells  solitary  or  united   in  5-8-celled 
families;  globose  or  subglobose,  15-37  n  diam.,  membrane  one- 
eighth  to  one-ninth  cell  diam.,  with  ridgy  or  wavy  prominences, 
running  in  various  directions,  and  intersecting  to  form  24-70 
angular  areas.     Fig. 32.     Mass.,  111.  Europe. 

T.  sporoides,  according  to  description  and  figures,  differs  only 
in  not  forming  families,  and  in  having  60-70  areas  formed  by 
the  more  numerous  ridges,  while  T.  reticularis  has  24-36.  T. 
Reinschii  shows  no  difference  whatever  in  the  description,  and 


146          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

the   figure   shows   only  a  slight  difference  in  the  form  of  the 
prominences  on  the  ridges. 

6.  T.   ARGUTA  (Reinsch)  Hansgirg,  1888,  p.   129;    Acantho- 
coccus  argutus  Reinsch,  1886,  p.   242,  PI.  XII,  figs.  19  and  23. 
Cells  solitary,  globose,  31-43  p  diam.,  membrane  very  thick,  up 
to  y>>  the  total  cell  diam.,  being  12-15  //. ;  ridges  wavy,  parallel, 
or  concentric,  the  projections  subacute.     111.  Europe. 

7.  T.  OBTUSA  (Reinsch)  Hansgirg,  1888,  p.   130;  Acantho- 
coccus  obtusus  Reinsch,    1886,   p.   243,   PI.   XII,   fig.   21.     Cells 
solitary,  globose,  34-37  ^  diam.,  membrane  }4>  cell  diam.,  with 
parallel  or  concentric  wavy  ridges,  waves  obtuse.     Mass. 

Europe. 

3.  CHLOROCHYTRIUM  Cohn,  1874,  p.  87. 
Cells  rounded  or  irregular,  with  parietal  chromatophore  and 
one  or  more  pyrenoids ;  asexual  reproduction  by  akinetes,  and 
by  biciliate  zoospores  with  red  stigma,  formed  by  repeated 
division,  escaping  singly  or  enclosed  in  a  .gelatinous' mass ; 
sexual  reproduction  by  biciliate  gametes  similarly  formed,  leav- 
ing the  mother  cell  in  a  gelatinous  mass,  within  which  they 
copulate,  producing  a  4-ciliate  zygote,  which  finally  penetrates 
the  tissue  of  the  host  plant,  and  there  develops  to  the  full  size. 
Marine  and  fresh  water. 

KEY  TO  THE  SPECIES  OF  CHI.OROCHYTRIUM. 

i.     In  fresh  water  plants.  2. 

i.     In  marine  plants.  3. 

2.     A  prolongation  of  the  cell  wall  remaining  where  the  zygote  entered 

the  host.  i.     C.  Lemnae. 

2.     Cell  entirely  enclosed,  no  prologation  to  surface  of  host. 

2.     C.  Knyanum. 

3.     Cells  with  pointed  base.  3.     C.  Schmitzii. 

3.     Base  of  cell  not  pointed.  4. 

4.     Cell  subhemispherical,  base  flattened.  4.     C.  dermatocolax. 

4.     Cells  globose  or  subglobose.  5.     C.  inclusion. 

i.  C.  LEMNAE  Cohn,  1874,  p.  87,  PI.  II;  Klebs,  1881,  p. 
250,  PI.  Ill,  figs,  i-io,  Endophytic  in  Lemna  trisnlca ;  cells 
ovoid,  ellipsoid  or  irregular,  up  to  ioo;udiam.;  sexual  reproduc- 
tion by  biciliate  pyriform  gametes,  formed  many  in  a  cell, 
escaping  by  the  breaking  of  the  cell  wall,  enclosed  in  a  gelat- 
inous vesicle,  within  which  they  conjugate  ;  the  subspherical 
zygote  escaping  and  coutinuing  active,  germinating  only  when 
falling  on  a  frond  of  Lemna  ;  here  attaching  itself  by  the  ciliate 
end,  and  pushing  a  tubular  extension  in  between  two  epidermis 
cells  of  the  host,  the  interior  part  expanding  and  the  protoplasm 
passing  into  it,  and  developing  to  the  normal  form  and  size ; 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  147 

the  entering  tube  remaining  as  a  cellulose  thread  with  a  knob- 
like  expansion  at  the  surface  of  the  host.  In  autumn  the  cell 
may  develop  to  a  thick-walled  akinete,  producing  gametes  in 
the  spring.  Fig.  33.  N.  H.  Europe. 

2.  C.  KNYANUM  Cohn  and  Szymanski  in  Kirchner,    1878, 
p.  102;  Klebs,   1881,  p.  255,  PI.  Ill,  figs.  11-15;  P.  B.-A.,  No. 
1518.     Cells  of  varying  form  but  usually  more  or  less  elongate, 
often  with  a  distinct  neck-like  prolongation  ;  up  to   100  //.  long  ; 
zoospores  formed  many  in  a  cell,  escaping  through  an  opening 
in   the    body  of   the   cell,   not    in    the   neck-like   prolongation, 
enclosed    in   gelatinous  vesicle,   from   which  they  soon  escape 
without  copulation  ;  ovoid  rather  than  pyriform,  soon  coming  to 
rest  and  penetrating  the  host  plant ;  thick-walled  akinetes  as  in 
C.   Lcmnae.     Sexual  reproduction  unknown.     In  old  fronds  of 
CeratophyUum,   Elodea,  Lemna  minor ;  L.  gibba,  etc.,  but   never 
found  in  L.  trisulca.     Mass.  Europe. 

As  P.  B.-A.,  No.  1517  was  distributed  an  endophytic  alga  in 
Sphagnum  from  Wood's  Hole,  Mass,,  under  the  name  of  C. 
Archcrianum  Hieronymus,  1887,  p.  296.  The  identification 
must  be  considered  doubtful,  in  view  of  the  scanty  description 
given  by  the  author  of  the  species,  and  of  some  peculiarities  of 
the  Wood's  Hole  plant,  which  may  make  even  its  generic  posi- 
tion uncertain. 

3.  C.  SCHMITZII  Rosenvinge,    1893,  P-  964,  fig.  56.     Cells 
clavate  or  ovoid,  with  rounded  apex  and  no  papilla,  and  pointed 
base;  up  to  370  /*  long  bygo/idiam.;  chromatophore  occupy- 
ing the  greater  part  of  the  cell  wall,  with  two  or  more  pyrenoids. 
Endophytic  in    various   crustaceous    marine   algae,    Petrocelis, 
Cruoria,  etc.     Greenland  to  Me.,  Alaska  to  Washington. 

Northern  Europe. 

4.  C.   DERMATOCOLAX    Reinke,    1889,   p.   88.     Cells   about 
30X20  /*,  seen  from  above  rounded  or  oval,  nearly  plane  below  ; 
external  surface  convex,  subhemispherical  or  subconical ;  asex- 
ual reproduction  by  numerous  zoospores,  4-6  /x  long,  escaping 
by  an  opening  in   the  end  of  the  papilla  formed  at  the  apex  of 
the  cell  at  the  time  of  fructification.     In  Chactoptcris plumosa, 
Sphacclaria  racemosa,  etc.     Greenland.  Northern  Europe. 

5.  C.  INCLUSUM  Kjellman,   1883,  p.   320,  PI.  XXXI,  figs. 
8-17  ;  P.  B.-A.,  No.  514.     Cell  globose  or  subglobose,  or  irreg- 
ular by  conditions  of  the  host  plant;  usually  80-100  /x.  diam., 
sometimes  more  than  twice  that  size  ;    wall  at  first  thin,  later 
thickening ;  chromatophore  covering  the  whole  surface,   with 
many  pyrenoids  ;  when  fruiting  a  cone-shaped  prolongation  is 


148          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

formed,  reaching  to  the  surface  of  the  host  plant ;  through  this 
the  zoospores  escape.  In  fronds  of  Iridaea,  Sarcophyllis,  etc. 
Greenland,  Alaska  to  Cal.  Northern  Europe. 

4.     RHODOCHYTRIUM  Lagerheim,  1893,  p.  43. 

Cell  dark  red  in  color,  with  rhizoidal  branching  prolongations 
among  the  cells  of  the  .host  plant ;  developing  numerous  bicili- 
ate  gametes  which  escape  through  a  narrow  neck,  and  unite  to 
form  a  zygote  which  penetrates  between  the  epidermis  cells  of 
the  host,  and  develops  a  cell  like  the  original  one  ;  the  gametes 
may  also  develop  to  such  a  cell  without  copulation.  Thick 
walled  resting  cells  also  formed,  whose  development  is  unknown. 

The  genus  seems  intermediate  between  algae  and  fungi ; 
whether  it  possess  chlorophyll  is  not  certain  ;  the  mycelium-like 
prolongations  appear  to  draw  nourishment  from  the  host.  Only 
one  species  is  known. 

R.  SPILANTHIDIS  Lagerheim,  1893,  p.  43,  PI.  II.  Cell 
spherical  to  ovoid,  or  irregularly  rounded,  100-200  /JL  diam., 
with  relatively  thin  wall^  communicating  with  the  exterior  of 
the  host  by  a  tube,  the  end  of  which  opens  to  give  passage  to 
the  gametes  ;  branching  prolongations  abundant,  diminishing 
to  about  4  fj.  in  the  final  divisions  ;  gametes  obconic  to  spherical 
with  two  cilia  attached  to  the  red  anterior  end  ;  resting  cells 
100-200' p.  diam. ,  with  thick,  stratified  wall.  In  stems  and  leaves 
of  Ambrosia  •artemisiifolia.  Fig.  34.  South  Carolina. 

So.  America. 

5.     CHLOROCYSTIS  Reinhard,  1885,  p.  4. 

Cells  as  in  Chlorochytrium,  but  asexual  reproduction  by  4-cil- 
iate  zoospores  ;  no  sexual  reproduction  known. 

C.  COHNII  (Wright)  Reinhard,  1885,  p.  4,  PI.  I;  Moore,  . 
1900,  p.  100,  PI.  X;  P.  B.-A.,  Nos.  565,  1121.  Cells  16-26 /u, 
diam.,  spherical  or  nearly  so,  chromatophore  bright  green, 
usually  somewhat  star-shaped  and  covering  only  part  of  the  cell 
wall,  but  sometimes  covering  the  whole,  with  one  large  pyre- 
noid  ;  zoospores  of  two  sizes,  one  spherical,  6-7  /u,  diam.,  the 
other  pyriform,  2.5-3.5  ^  diam.,  both  4-ciliate,  escaping  through 
an  opening  in  the  cell  wall ;  either  kind  of  spore  can  germinate, 
and  no  conjugation  has  been  observed.  Fig.  35.  Greenland  to 
Mass.  Europe. 

This  species  forms  dense  coatings  on  Enteromorpha ;,  Schizo- 
nema  and  other  marine  plants,  often  penetrating  into  the  tissue 
of  the  host,  but  apparently  never  entirely  covered  by  the  latter. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  149 

6.     CHARACITM  A.  Braun  in  Kiitzing,  1849,  p.  208. 

Cells  with  cup-shaped  chromatophore  and  one  pyrenoid,  from 
narrowly  lanceolate  or  subcylindrical  to  broadly  ellipsoid  or 
subglobose,  often  more  or  less  bent,  attached  by  a  pointed  end 
or  by  a  stipe-like  prolongation  to  the  substratum  ;  asexual  repro- 
duction by  biciliate  zoospores  of  two  sizes,  escaping  by  a  hole 
or  slit  in  the  cell,  also  by  akinetes ;  the  occurrence  of  gametes 
is  doubtful. 

A  genus  of  many  species  differing  much  in  size  and  propor- 
tions of  the  cell,  attached  to  larger  fresh  water  algae  or  other 
objects;  common,  but  easily  overlooked.  Borzi,  1895  has  re- 
moved a  number  of  species,  forming  a  new  genus,  Characiopsts, 
allied  to  the  Confervaceae  ;  some  of  the  species  remaining  in 
Characium  are  imperfectly  known,  and  may,  when  more  fully 
studied,  also  require  removal. 

KEY  TO  THE  SPECIES  OF  CHARACIUM. 

I.     Growing  on  animals.  2. 

i.     Not  on  animals.  3. 

2.     Ovoid  or  broadly  ellipsoid.  8.     C.  De  Baryanum. 

2.     Elongate.  n. 

3.     Sessile.  i.     C.  sessile. 

3.     With  longer  or  shorter  stipe.  4. 

4.     Stipe  with  distinct  basal  disk.  u.     C.  Pringsheimii. 

4.     Stipe  without  distinct  basal  disk.  5. 

5.     Obtuse.  6. 

5.     Acute.  10. 

6.     Globose  to  broadly  ellipsoid.  7. 

6.     Lanceolate  to  ellipsoid.  8. 
7.     Having  a  rounded  stopper-like  body  at  apex  of  cell. 

6.     C.  obtusum. 

7.     Without  such  body.  5.     C.  heteromorphum. 

8.     Narrowly  lanceolate  to  linear.  4.     C.  strict um. 

8.     Ellipsoid.  9- 

9.     Stipe  about  4  A*  long.  3-     C.  Naegehi. 

9.     Stipe  extremely  short.  2.     C.  Sieboldii. 

10.     Diam.  15  M  or  more.  9-     C.  acuminatum. 

10.     Diam.  8  M  or  less.  7-     C.  ambiguum. 

ii.     With  slender  prolonged  summit.  12.     C.  gracilipes. 

ii.     With  blunt  summit.  10.     C.  cylindricum. 

i.  C.  SESSILE  Hermann,  1863,  p.  26,  PI.  VII,  fig.  6  ;  Wolle, 
1887,  p.  177,  PI.  CLIX,  fig.  i.  Cells  7-9  A*  diam.,  at  first 
globose,  later  developing  a  small  apiculum,  but  continuing 
sessile.  N.  J.  .  Europe. 


150          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

2.  C.  SIEBOLDII  A.  Braun  in  Kiitzing,  1849,  p.  208;    1855, 
p.  32,  PI.  III. A.  ;  G.  S.  West,  1905,  p.  286.     Cells  15-25X4-9^, 
erect,   straight,    when  young   elongate-ellipsoid   or   lanceolate, 
rather  obtuse ;  when  adult  short  ellipsoid  or  obovoid,  obtuse ; 
stipe  short,  without  basal  disk.     Barbados.  Europe. 

3.  C.  NAEGELII  A.  Braun  in  Nageli,   1848,  p.  86,  PI.  III. 
D.  ;  Wolle,  1887,  p.  178,  PI.  CUX,  fig.  4;   Rabenhorst,  Algen, 
No.  512.     Cells  20-42X7-18  p.,  erect,  straight,  at  first  narrowly 
lanceolate,    later    oblong    or    ellipsoid,    always    obtuse ;    stipe 
slender,  about  4 p.  long,  base  not  swollen.     Mass.,  Pa.,  Neb. 

Europe. 

4.  C.  STRICTUM  A.  Braun,  1855,  p.  37,  PI.  V.  A.  ;   P.  B.-A. 
No.   1371.     Cells  23-30X6-7  p.,   narrowly  lanceolate  or  linear- 
oblong,   straight,   apex   obtuse    or   rounded ;    stipe  very  short, 
slightly  swollen  at  the  base.     Mass.,  Cal.  Europe. 

5.  C.  HETEROMORPHUM  (Reinsch)  Wolle,  1887,  p.  178,  PI. 
ClylX,    fig.  6;    Hydrianum   heteromorphum  Reinsch,    1875,   P- 
80,  PI.  XI,  fig.  3.     Cells  20X8-18  p,  globose  to  ellipsoid,  taper- 
ing below  into  the  stipe  ;  zoospores  escaping  by  a  wide  opening 
at  the  summit ;  cell  after  escape  of  the  zoospores  subcylindrical, 
about  6  p  diam.     Pa.  Europe. 

It  may  be  a  question  whether  the  cell  continues  to  live  after 
the  emission  of  the  zoospores ;  Reinsch's  brief  note  does  not 
give  sufficient  information. 

6.  C.  OBTUSUM  A.   Braun,    1855,    p.  39,   PI.    III.E.      Cell 
straight,   22-33  f-  long.    at  nfst  oblong-ellipsoid,  later   broadly 
ovoid  and  about  half  as  broad  as  long  ;  with  a  rounded  stopper- 
like  body  at  the  apex  of  the  cell;    stipe  very  short,  slightly 
thickened  at  the  base.     Mass.  Europe. 

7.  C.   AMBIGUUM  Hermann,    1863,   p.    26,    PI.  VII,  fig.  9; 
Wolle,    1887,  p.    177,   PI.   CL,IX,   fig.   5.     Cells  24-32X4-8  /i, 
erect,  obliquely  and  narrowly  lanceolate  or  ensiform,  uniformly 
attenuate  to  each  end,  apex  cuspidate,  with  a  sometimes  curved 
apiculum  ;  stipe  short,  slender,  not  swollen  at  the  base.     Mass., 
Pa.  Europe. 

8.  C.  De  Baryanum  (Reinsch)  nov.  comb.  ;  Dadylococcus  De 
Baryanus  Reinsch  ,1875,  p.  78,  PI.  XI,  fig.  i  ;   i879a,  p.  38,  PI. 
I,  figs.  21-24.     Cells  oblong  to  ovoid,  20-25X30-40  /A,  with  rela- 
tively  stout   stipe,  about    15/11  long,  swollen   at   the   point   of 
attachment  into  a  small,  thick  disk.     On  the  minute  crustacean, 
Cyclops.     Mass.,  Mich.  Europe. 

Reinsch  records  observing  the  development  of  the  mature 
plant  just  described  from  a  motile  cell  about  25  /x  diam.,  with 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  151 

red  stigma  ;  also  the  division  of  the  protoplasm  of  an  adult  cell 
into  several  daughter  cells  ;  apart  from  this,  the  development  is 
unknown. 

9.  C.   ACUMINATUM  A.   Braun   in   Kiitzing,    1849,  p.  892  ; 
Hydrocytium    a  cumin  a  him    A.    Braun,    1855,   p.   26,    PI.    II. A. 
Cells  35-40X15-20  /A,  oblong  or  ovoid,  apex  shortly  acuminate, 
stipe  short,  sometimes  slightly  swollen  at  the  base.     Mass. 

1  \nrope. 

10.  C.  CYLINDRICUM  Lambert,  1909,  p.  65,  PI.  79,  figs.  10-13  ; 
P.  B.-A.,  No.  1269.    Cell  24-430/11  long,  10-20 /xdiam.,  cylindrical 
with  rounded    apex  ;    tapering  at   the  base  into  a  short  stipe, 
without    basal  disk.      On   the    minute    crustacean   Branchipus 
vernalis.     May.     Mass. 

11.  C.  PRINGSHEIMII  A.  Braun,  1855,  p.  106 ;  Wolle,  1887, 
p.  177,  PI.  CLIX,  fig.  3  ;  Wittr.   and  Nordst.,   Alg.   Exsicc., 
No.  153.     Cells  20-25X6-10  p.,  erect,  somewhat  oblique,  ovoid  or 
lance-ovoid,  shortly  acuminate,  apiculum  usually  oblique  ;  stipe 
short,  expanding  below  into  a  minute,  yellowish  disk.     Mass., 
Pa .  Europe. 

12.  C.  GRACILIPES  Lambert,  1909,  p.  65,  PI.  79,  fig.  3-6 ; 
P.  B.-A.,  No.  1270.     Cell  regularly  curved,  80-480 /x  long,  7-13/4 
diam.,  middle  part  fusiform,  tapering  above  into  a  long  seta, 
below  into  a  long  filiform  stipe,  attached  to  the  substratum  by 
very  minute  rhizoids.     On  Branchipiis  vernalis.    Fig.  36.    May. 
Mass. 

7.     CODIOLUM  A.  Braun,  1855,  p.  19. 

Frond  unicellular,  ovoid  to  clavate  or  sub-cylindric,  the  cell 
wall  prolonged  below  into  a  longer  or  shorter  stipe,  attached  by 
a  simple  or  forked  expansion  ;  chromatophore  covering  the  cell 
wall  or  more  or  less  broken,  with  several  pyrenoids ;  asexual 
reproduction  by  quadriciliate  /oospores,  many  in  a  cell ;  also  by 
larger  aplanospores  (?). 

The  structural  plan  of  all  the  species  of  this  genus  is  identi- 
cal ;  a  deep  green  cell  with  thick  wall,  prolonged  below  into  a 
slender,  colorless  stipe ;  but  the  proportions  and  dimensions 
vary  very  much.  The  colored  part,  known  as  the  clava,  may 
be  broadly  oval,  up  to  120  p.  diam.  ;  or  it  may  be  almost 
cylindrical,  not  over  25  p  diam.  The  total  length  varies  be- 
tween 175  and  2700  p.,  the  shorter  forms  having  the  largest 
diameter  of  clava,  and  the  longer  forms  tapering  very  gradually 
from  the  base  to  the  only  slightly  clavate  apex  ;  in  these  slender 


152  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

forms  the  clava  may  occupy  from  one-tenth  to  three-fourths  of 
the  total  length,  the  clava  and  stipe  may  be  plainly  distinct,  or 
may  pass  into  each  other  imperceptibly.  The  plants  are  mostly 
gregarious,  often  growing  in  abundance  over  long  stretches  of 
shore  between  tide  marks,  either  alone  or  in  company  with  other 
small  algae  ;  though  comparison  of  specimens  collected  at  dif- 
ferent times  and  places  will  show  many  gradations  of  form,  it  is 
usually  found  that  all  the  plants  of  one  collecting  are  uniform 
in  character.  Quite  a  number  of  species  have  been  described, 
but  it  has  seemed  best  here  to  recognize  only  three,  including 
others  under  them  as  forms. 

KEY  TO  THE  SPECIES  OF  CODIOLUM. 

i.     Growing  among  the  tissues  of  other  algae.  i.     C.  Petrocelidis. 

i.     Free.  2. 

2.     Clava  ovoid,  much  thicker  than  the  stipe.         2.     C.  gregarium. 

2.     Clava  narrowly  clavate,  not  much  thicker  than  the  stipe. 

3.     C.  pusillum. 

1.  C.  PETROCELIDIS Kuckuck,  1894,  p.  259,  fig.  27.     Fronds 
endophytic,   in    tissue   of   Petrocelis ;   clava  ovoid   or   obovoid, 
65-90X20-30  p.;  stipe  very  slender,  usually  terminating   below 
in  a  point.     Me.  to  Mass.  Northern  Europe. 

The  cells  are  developed  among  the  vertical  filaments  of  the 
host,  and  can  be  detected  only  by  microscopic  examination. 
The  endophytic  habit  of  this  species  renders  the  stipe  unneces- 
sary, and  it  has  become  little  more  than  a  rudiment. 

2.  C.  GREGARIUM  A.   Braun,    1855,   p.  20,   PL  I ;  Farlow, 
i88i,p.  58;  P.  B. -A.,  No.  165.     Clava  ovoid,  250-500X65-100/1, 
sharply  distinguished   from  the  stipe,  which  varies  from   600- 
1000  n  in  length,  and  20-30  p.  in  thickness.     Occurs  usually  in 
company  with  Calothrix,  etc.,  on  rocks  and  shells,  along  the 
New  England  coast ;  rarely  found  unmixed,  or  forming  so  large 
a  proportion  of  the  mixture  as  to  be  noticeable  except  in  micro- 
scopic examination.     Fig.  37.     Me.  to  N.  Y.  Europe. 

Forma  intermedium  (Foslie)  nov.  comb.  ;  C.  intermedium 
Foslie,  1887,  p.  193,  PI.  II,  figs.  1-12  ;  Wittr.  and  Nordst., 
Alg.  Exsicc.,  No.  954.  Stipe  170-250X25-40^  ;  clava  i5o-3ooX 
55- 1 10  p..  Me.  Northern  Europe. 

An  extreme  form,  with  much  swollen,  sometimes  almost 
spherical  clava,  and  short,  stout  stipe.  It  has  been  found 
among  Calothrix  scopulorum  on  islands  off  Portland  harbor, 
Maine. 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  153 

3.  C.  PUSILUM  (Lyng.)  Kjellinan,  1883,  p.  318.  Fronds 
long,  very  slender  at  base  of  the  stipe,  widening  slowly  to  the 
clava,  which  is  seldom  over  60  p.  diam. 

Forma  TYPICUM  Wittr.  and  Nordst.,  Alg.  Exsicc.,  No.  457  ; 
P.  B.-A.,  No.  1126.  Widening  uniformly  from  base  of  stipe  to 
summit  of  clava ;  stipe  about  twice  as  long  as  clava ;  total 
length  up  to  2  mm.  ;  greatest  diam.  about  60-70  p.. 

The  typical  C.  pusillum  has  been  found  in  America  only  in 
Eastern  Maine,  where  it  forms  velvety  coatings  on  rocks  about 
half-tide  level,  unmixed  with  any  other  alga,  and  forming  ex- 
tensive patches  on  exposed  rocks. 

Forma  AMERICANUM  Wille,  in  P.  B.-A.,  No.  869.  Stipe 
5-10  times  as  long  as  clava,  otherwise  like  the  type.  On  rocks 
near  high  water  mark,  at  Marblehead,  Mass.,  forming  a  coating 
unmixed  with  other  plants. 

Forma  longipes  (Foslie)  nov.  comb.  ;  C.  longipes  Foslie, 
1881,  p.  n,  PI.  II,  fig.  4;  P.  B.-A.,  No.  26.  Division  be- 
tween stipe  and  clava  usually  marked,  the  lower  part  of  clava 
being  about  double  the  diam.  of  the  summit  of  the  stipe ;  stipe 
30-60  fj.  diam.,  as  long  as  clava  ;  total  length  up  to  1200  yu,,  larg- 
est diameter  100  p.. 

This  form  is  abundant  along  the  coast  of  Maine,  forming  a 
practically  unmixed  coating  on  rocks  at  half  tide  over  consid- 
erable stretches.  In  drying,  the  individual  plants  adhere  in 
such  a  way  as  to  leave  the  transparent  stipes  exposed  in  minute 
spots,  giving  the  surface  a  mottled  appearance,  characteristic 
and  readily  recognized,  but  not  easy  to  describe.  Something 
of  the  same  appearance  is  found  in  the  other  forms  of  these 
species,  but  not  to  the  same  extent. 

Family  2.     PROTOSIPHONACEAE. 

Unicellular,  terrestrial,  relatively  large  algae,  multinucleate ; 
chromatophore  large  and  net-like  ;  cells  often  giving  out  color- 
less prolongations,  developing  into  normal  cells  at  the  end  ; 
sexual  reproduction  by  zoogametes,  asexual  reproduction  by 
zoospores. 

Only  one  genus. 

PROTOSIPHON  Klebs,  1896,  p.  221. 

Frond  unicellular,  multinucleate,  with  net-like  chromatophore 
and  many  pyrenoids  ;  in  form  spherical,  cylindrical,  or  irregu- 
lar, with  a  slender,  usually  unbranched  prolongation,  penetra- 
ting the  moist  ground  on  which  it  grows ;  cells  dividing  vege- 


154          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

tatively,  the  divisions  each  sending  down  root-like  prolongations. 
Sexual  reproduction  by  biciliate  gametes,  formed  several  to 
many  in  a  cell,  and  by  conjugation  forming  a  star-shaped 
zygote,  which  after  a  period  of  rest  develops  directly  to  a  normal 
plant.  Under  certain  conditions  the  gametes  do  not  conjugate, 
but  assume  a  rounded  form,  and  soon  develop  to  a  normal  plant. 
Asexual  reproduction  by  aplanospores  formed  many  in  a  cell, 
often  colored  red  with  haematochrome  ;  these  have  a  longer  or 
shorter  resting  period,  and  either  develop  directly  to  normal 
plants,  or  produce  biciliate  gametes,  similar  to  those  already 
described.  Only  one  species. 

P.  BOTRYOIDES  (Kiitz.)  Klebs,  1896,  p.  222,  PL  I,  figs.  1-16, 
P.  B.-A.,  No.  1268  ;  Botrydium  granulatum  Rostafinski  and 
Woronin,  1877,  p.  16  in  part,  PI.  V:  Tilden,  American  Algae, 
No.  45,  in  part.  Exposed  part  )4-5  mm.  diam.,  vegetative  di- 
vision usually  into  4-16  cells;  zoospores  15-20X5-8^;  aplano- 
spores globose,  about  40  /A  diam.  On  moist  ground,  especially 
clay.  Fig.  38.  Conn.,  Minn.,  Cal.  Europe. 

This  species  seems  to  occur  usually  in  connection  with  one  or 
both  species  of  Botrydium,  and  was  described  by  Rostafinski 
and  Woronin  as  a  condition  of  that  genus.  In  Miss  Tilden's 
specimens  it  is  in  company  with  B.  Wallrothii  Kiitz. 

Family  3.     HALOSPHAERACEAE. 

Unicellular,  spherical,  plankton  algae  of  relatively  large  size  ; 
cell  thin-walled,  uninucleate,  with  numerous  disk-shaped  chro- 
matophores,  usually  with  pyrenoids.  Asexual  reproduction  by 
obconic  zoospores,  or  by  aplanospores.  Fresh  water  and  marine. 

KEY  TO  THE  GENERA  OF  HALOSPHAERACEAE. 

i.     Reproduction  by  numerous  aplanospores.    2.     EXCENTROSPHAERA.   • 
T.     Reproduction  by  division  into  2,  rarely  4  cells. 

i.    EREMOSPHAERA. 

i.     EREMOSPHAERA  De  Bary,  1858,  p.  56. 

Cells  solitary,  uninucleate,  free,  large,  spherical,  with  num- 
erous small  chromatophores,  either  parietal  or  radiating  from 
the  center,  with  1-4  pyrenoids;  cell  wall  normally  thin,  but 
sometimes  gelatinizing  freely  ;  cells  often  showing  several  con- 
centric walls  ;  cells  dividing  into  2,  rarely  4  cells,  freed  by  the 
breaking  up  of  the  mother  cell  wall ;  resting  cells  with  thick 
walls  and  brick-red  contents,  ultimately  resuming  the  normal 
condition.  Fresh  water.  Only  one  species. 

E.  VIRIDIS  De  Bary,  1858,  p,  56,  PI.  VIII,  fig.  26;  Wolle, 
1887,  p.  200,  PL  XCLXVII,  fig.  ii  ;  P.  B.-A.,  No.  458.  Fig.  39. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  155 

Characters  of  the  genus ;  appearing  under  two  forms  : 

Var.  MAJOR  Moore,  1901,  p.  311,  PI.  X,  figs,  i  and  2;  P. 
B.-A.,  No.  1315.  Cells  70-150  p.  diam. 

Var.  MINOR  Moore  1901,  p.  311,  PI.  X,  fig.  3.  Cells  30-50/01 
diam.  Greenland,  Me.,  Mass.,  Conn.  Europe. 

The  unusually  large  size  of  this  unicellular  alga,  the  perfect 
spherical  form,  bright  green  color,  and  varied,  often  quite  sym- 
metrical arrangement  of  the  small  chromatophores,  make  it  an 
interesting  object.  Chodat,  1895,  describes  forms  and  modes 
of  propagation  which  if  confirmed  would  change  its  position 
among  the  green  algae,  and  also  identify,  as  stages  of  growth, 
other  supposedly  distinct  forms.  The  long  continued  and  care- 
ful studies  by  Moore  failing  to  show  anything  of  the  kind,  the 
present  position  seems  the  best  for  it. 

2.  EXCENTROSPHAERA  Moore,  1901,  p.  322. 
Cells  uninucleate,  solitary,  free,  large ;  spherical,  ellipsoidal, 
or  sometimes  irregular  and  angular ;  chromatophores  large, 
angular,  more  or  less  radiately  arranged,  covering  the  entire 
wall,  each  with  numerous  minute  pyrenoids ;  asexual  reproduc- 
tion by  numerous  aplanospores,  escaping  by  an  opening  in  the 
cell  wall,  and  increasing  in  size  until  the  normal  dimensions  are 
reached.  Fresh  water.  Only  one  species. 

E.  VIRIDIS  Moore,  1901,  p.  322,  PI.  XII.     Cells  bright  green, 
22-55  P-  diam.,  spores  2-3  //,  diam.     Fig.  40.     Vt.,  Mass. 

Europe. 

In  general  appearance  resembling  small  forms  of  Eremosphaera 
with  which  it  often  occurs ;  very  likely  the  ' '  Centrosphaera- 
state  ' '  of  Eremosphaera  described  by  Chodat  should  really  be 
referred  to  this  genus. 

Family  4.     SCENEDESMACEAE. 

Unicellular  ;  cells  spherical,  or  developing  into  various  forms, 
with  bell-shaped  chromatophore,  solitary,  or  united  by  gelatine 
in  more  or  less  regular  colonies  ;  asexual  reproduction  by  aplan- 
ospores. Fresh  water,  rarely  marine  plants. 

KEY  TO  THE  GENERA  OF  SCENEDESMACEAE. 

i.     Living  in  the  cells  of  lower  animals.  i.     ZOOCHI,OREI,I,A. 

i.     Not  living  in  the  cells  of  animals.  2. 

2.     Cells  contained  in  an  extensive,  gelatinous  thallus.  3. 

2.     No  external  gelatinous  thallus.  5. 

3.     Sporangia  much  larger  than  vegetative  cells.          12.     HORMOTILA. 


156  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

3.     Sporangia  not  specialized.  4. 

4.     Thallus  a  membrane  or  mass.  10.     SCHIZOCHLAMYS. 

4.     Thallus  a  simple  or  branching  filament.         n.     ELAKATOTHRIX. 
5.     Mature  cell  solitary.  6. 

5.     Mature  cells  united  in  colonies.  12. 

6.     Mother  cell   elongate,  acicular  or  fusiform,  dividing  by  oblique 
walls  into  daughter  cells.  2.     RHAPHIDIUM. 

6.     Daughter  cells  formed  in  the  interior  of  the  mother  cell.  7. 

7.     Cells  angular,  often  with  much  developed  projections.  8. 

7.     Cells  rounded.  10. 

8.     Cells  with  distinct  polyedral  central  mass.          7.     TETRAEDRON. 

8.     Cells  of  rays  from  a  common  center,  without  distinct  central  mass. 

9- 

9.     Rays  unbranched.  9.     CERASTERIAS. 

9.     Rays  di-trichotomously  divided.  8.     THAMNIASTRVM. 

10.    Cells  with  spines.  5.     CHODATELLA. 

10.     Cells  without  spines.  n. 

ii.     Cells  ovoid.  4-     OOCYSTIS. 

ii.     Cells  reniform.  6.     NEPHROCYTIUM. 

ii.     Cells  spherical.  3.     PALMELLOCOCCUS. 

12.     Cells  elongate,  side  by  side  in  a  single  or  double  series. 

13.     SCENEDESMUS. 

12.     Cells  arranged  symmetrically  about  a  center.  13. 

13.     Cells  arranged  in  one  plane.  14.     CRUCIGENIA. 

13.     Cells  radiating  in  all  directions.  .       14. 

14.     Cells  lunate  or  sickle-shaped.  19. 

14.     Cells  not  lunate  or  sickle-shaped  ;  united  to  the  centre  by  gelati- 
nous strands  or  stipes.  15. 
15.     Stipes  short,  unbranched.  16. 
15.     Stipes  branched.  17. 

16.     Cells  with  spinous  projections.  18.     SORASTRUM. 

16.     Cells  without  spinous  projections.  17.     COEI,ASTRUM. 

17.     Cells  in  series  on  gelatinous  strands.  21.     DICTYOCYSTIS. 

17.     Cells  at  the  ends  of  gelatinous  strands.  18. 

18.     Cells  spherical.  19.     DICTYOSPHAERIUM. 

18.     Cells  reniform,  ovoid  or  cordate.'  20.     DIMORPHOCOCCUS. 

19.     Cells  united  by  the  convex  sides.  15.     SELENASTRUM. 

19.     Cells  in  no  definite  order  in  a  common  gelatinous  envelop. 

16.     KIRCHNERIELI.A. 

i.     ZOOCHLORELLA  Brandt,  1882,  p.  140. 

Cells  free,  minute ;  spherical,  ellipsoid  or  flattened,  with  chro- 
matophore  covering  part  of  the  cell  wall,  apparently  without 
pyrenoid  ;  asexual  reproduction  by  aplanospores  formed  by  suc- 
cessive division  in  a  cell,  freed  by  rupture  of  the  wall. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  157 

The  two  species  noted  below  live  in  various  lower  fresh  water 
animals ;  they  are  so  intimately  associated  with  the  hosts  that 
they  were  long  supposed  to  be  integral  parts  of  the  same ;  in 
many  cases  the  alga  cell  divides  at  the  same  time  as  the  host 
cell.  Beyerinck,  1890,  has  proposed  a  genus  Chlorella,  includ- 
ing these  species  and  some  free  species,  which  latter  he  thinks 
have  been  included  under  Chlorococcnm  ;  it  is  difficult  to  see 
why  Zoochlorella  should  be  superseded,  unless  the  ground  is  that 
it  was  described  by  a  zoologist,  and  not  by  a  botanist. 

KEY  TO  THE  SPECIES  OF  ZOOCHLORELLA. 

i.     Cells  3-6  n  diarn.  i.     Z.  conductrix. 

i.     Cells  1.5-3  ,u  diam.  2.     Z.parasitica. 

1.  Z.  CONDUCTRIX  Brandt,   1882,  p.   140.     Endozoic ;  cells 
3-6  p.  diam.,  in  tissues  of  Hydra  and  allied  fresh  water  organ- 
isms.    Fig.  41.     Mass.  Europe. 

2.  Z.  PARASITICA  Brandt,  1882,  p.  140;  P.  B.-A.,  No.  1515. 
Endozoic;  cells  1.5-3  M  diam.;  in  tissues  of  Spongilla,  Ophry- 
dium  and  other  fresh  water  organisms.     Mass.  '  Europe. 

2.     RHAPHIDIUM  Kiitzing,  1845,  P-  H4- 

Cells  elongate,  acicular  or  fusiform,  straight  or  variously 
curved,  writh  pointed  or  rounded  ends ;  chromatophore  nearly 
covering  the  cell  wall,  usually  without  pyrenoid ;  cell  dividing 
by  oblique  cross  walls  into  2-32  daughter  cells,  which  separate 
soon  after  attaining  their  full  shape  and  size  ;  less  frequently 
remaining  attached  in  bundles,  or  to  the  wall  of  the  mother 
cell.  Widely  distributed  fresh  water  plankton  algae. 

KEY  TO  THE  SPECIES  OF  RHAPHIDIUM. 

i.     With  a  long  seta  at  each  end.  4.     R.  setigerum. 

i.  Without  setae.  2. 

2.  Cells  12-25  diam.  long,  ends  very  acute.  i.  R.  fa  leaf  urn, 

2.  Cells  3-12  diam.  long,  ends  obtuse  or  apiculate.  3. 

3.     Cells  variously  twisted  and  curved.  2.     R.  convolutum. 

3.     Cells  straight  or  nearly  so,  relatively  stout.  3.     R.  Braunii. 

i.  R.  FALCATUM  (Corda)  Cooke,  1882,  p.  19,  PI.  VIII,  fig.  4  ; 
R.  polymorphum  Wolle  1887,  p.  197;  P.  B.-A.,  No.  1179.  Cells 
bright  or  yellowish  green,  slender,  fusiform,  at  the  middle 
sometimes  swollen,  sometimes  constricted  ;  ends  very  acute  ; 
straight  or  variously  curved  ;  1.5-3.5  P-  diam.,  15-25  diam.  long, 
up  to  90  /u, ;  usually  united  2-32  in  a  bundle.  Greenland  to  Fla. 
and  westward,  Porto  Rico.  ]turope. 

A  common  and  variable  species ;  Micrasterias  falcatus  is  the 
first  name  used  for  any  of  the  forms  now  included  in  this  species, 


158  TUFTS  COLLEGE;  STUDIES,  VOL.  II,  No.  3 

and  must  be  considered  as  the  type  ;  other  forms  found  with  us 
are  as  follows  :  — 

Var.  ACICULARE  (A.  Br.)  Hansgirg,  1886,  p.  118;  R.  poly- 
morphum  var.  aciculare  Wolle,  1887,  p.  197,  PI.  CIvX,  figs.  22 
and  23  ;  R.  aciculare  Wittr.,  Nordst.  and  L,agerh.,  Alg.  Exsicc., 
No.  1243.  Very  slender,  1.5-3  f1  diam.,  15-20  diam.  long, 
acicular,  straight  or  slightly  curved,  usually  solitary.  Mass., 
Pa.,  Neb.  Europe. 

Var.  FUSIFORME  (Corda)  Hansgirg,  1886,  p.  119;  R.  fascicu- 
latum  Nageli,  1848,  p.  82,  PI.  IV. C,  fig.  i;  P.  B.-A.,  No. 
1512.  Fusiform,  gradually  tapering  to  each  end;  diam.  2-6 /A, 
cells  12-20  diam.  long,  straight  or  more  or  less  curved,  fascicu- 
lately  clustered.  Fig.  42.  Mass.,  Pa.  Europe. 

2.  R.  CONVOLUTUM  (Corda)  R'abenhorst,  1868,  p.  46  ;  Wolle, 
1887,  p.  198,  PL  CL,X,  figs.  1-5.     Cells  variously  curved,  con- 
volute or  contorted,  3.5-5  ^  diam.,  3-12  diam.  long,  ends  obtuse 
or  apiculate  ;  cells  usually  solitary.     Me.,  Mass.,  Pa.,  Neb. 

Europe. 

3.  R.   BRAUNII   Nageli   in   Kiitzing,   1849,  p.  891  ;  Wolle, 
1887,  p.   198,  PI.  ClyX,  figs.   26  and  27;  Wittr.,  Nordst.  and 
L,agerh.,    Alg.   Exsicc.,    No.    1245.      Cells  cyclindric-fusiform, 
relatively  short  and  stout,  5-8  p.  diam.,  4-6  diam.  long,  straight 
or  somewhat  curved,  slightly  tapering  at  both  ends,  subobtuse  ; 
solitary  or  in  pairs,  rarely  3  or  4  together.     Mass.,  Pa.    Europe. 

4.  R.  SETIGERUM  (Schroder)  W.  and  G.  S.  West,  1901,  p. 
122.     Rcinschiella  ?  sctigera  Schroder,  1897,  p.  489.     Cells  fusi- 
form, the  apices  attenuate  into  long,  fine  setae.     Diam.  3-6  /n ; 
length  60-85  fj. ;  chromatophore  with  one  pyrerioid.     Mass. 

Europe. 

R.  FRACTUM  W.  and  G.  S.  West,  1899,  p.  279,  from  Domin- 
ica, is  described  as  near  to  R.  Braunii,  but  somewhat  narrower ; 
the  special  character  given  is  the  division  of  the  chromatophore 
into  four  subequal  parts.  As  the  description  was  made  from 
dried  specimens,  it  is  not  impossible  that  this  appearance  is  due 
to  the  preparation  for  cell  division,  in  which  case  the  distinction 
from  R.  Braunii  would  not  be  clear. 

3.     PALMELLOCOCCUS  Chodat,  1894,  p.  429. 

Cells  free,  globose,  with  wall  of  two  or  more  layers,  with  one 
or  more  disk-shaped  chromatophores  without  pyrenoid,  often 
concealed  by  an  orange-red  coloring  ;  asexual  reproduction  by 
bipartition  of  the  cell,  also  by  division  into  numerous  aplano- 
spores,  which  escape  in  a  gelatinous  vesicle. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  159 

KEY  TO  THE  SPECIES  OF  PALMELI.OCOCCUS. 
i.     Chrouiatophores  several,  no  coloring  matter  present. 

3.     P.  thermalis. 
i.     Chromatophore     single,    usually    concealed     by    reddish     coloring 

matter.  2. 

2.     Cells  3-15  fj.  diam. ;  plant  of  greenhouses,  etc.       i.     P.  miniatus. 
2.     Cells  10-40  /j.  diam. ;  plant  of  salt  marshes.  2.     P.  marintis. 

1.  P.  MINIATUS  (Leiblein)  Chodat,   1894,  P-  429,  PI.  XXV, 
figs.  11-26;    1902,  p.  183,  fig.  80;   Phyk.  Univ.,   No.  689;  Pro- 
tococcns  viridis  var.  miniatus  Wolle,  1887,   p.   181,    PL  CL,XII, 
fig.  5.     Cells  3-15  /*  diam.,  orange  red,  with  more  or  less  oil; 
forming   a   gelatinous   coating   on   walls   of  greenhouses,    etc. 
Fig.  43.     Very  generally  distributed. 

2.  P.  MARINUS  Collins,  1907,   p.  198;  P.  B.-A.,No.  1316.* 
Cells   10-40  fj.  diam.,  including   wall  about    2  p   thick;    color 
from  deep  orange  to  green ;  aplanospores  8-64  in  a  cell,  spore 
wall  quite  thick  while  still  in  the  mother  cell ;  mass  of  spores 
retaining  the  spherical  form  long  after  the  disappearance  of  the 
mother   cell  wall.     Among  various  algae  in  salt  marsh  pools. 
Maine. 

3.  P.  THERMALIS  G.  S.  West,  1904,  p.  287,  PI.  CCCCIvXIV, 
fig.  21.     Cells   2-6  fj.  diam.,  deep   green,  membrane   thin   and 
firm  ;  chromatophores  2  or  3,  parietal  disks  ;  aplanospores  4-16 
in  a  cell.     In  hot  springs.     Dominica. 

4.     OOCYSTIS  Nageli  in  A.  Braun,  1855,  p.  94. 

Cells  ovoid  ;  chromatophores  single  or  small  parietal  disks  or 
grains,  with  or  without  pyrenoid ;  asexual  reproduction  by 
division  of  the  contents  into  2-8  daughter  cells,  in  the  expanded 
membrane  of  the  mother  cell,  sometimes  a  third  generation 
formed  before  the  mother  cell  wall  breaks  up. 

Quite  a  number  of  species  have  been  described  in  this  genus, 
four  of  which  have  been  reported  in  America  ;  it  is  likely  that 
others  will  be  found.  Only  numbers  3  and  4  can  be  considered 
as  safely  identified  with  the  European  forms  of  the  same  names. 

KEY  TO  THE  SPECIES  OF  OOCYSTIS. 

i.     Cells  with  a  tubercular  thickening  at  each  end.       3.     O.  solitaria. 

i.     Cells  without  tubercular  thickening.  2. 

2.     Chromatophores  several  in  a  cell.  4.     O.  crassa. 

*By  mistake  the  combination  Pleurococcus  marinus.vras  used  in  the 
description  in  Rhodora ;  the  following  text  indicates  that  Palmello- 
coccus  is  meant;  the  proper  form  is  used  in  P.  B.-A,  No.  1316. 


160  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

2.     Chromatophore  entire  or  halved.  3. 

3.     Ends  rounded.  i.     O.  Borgei. 

3.     Ends  acute  or  subacute.  2.     O.  lacustris. 

1.  O.  BORGEI  Snow,  1903,  PI.  II,  fig.  7.     Cells  ellipsoidal  or 
slightly  fusiform,  ends  rounded,  wall  uniform  or  slightly  thick- 
ened at  one  end,  with  no  projection,  9-13  /x  long  ;  chromatophore 
single,  with  pyrenoid  ;  cells  in  colonies  of  two  or  a  multiple  of 
two,  free  or  united  in  a  common  gelatine.     In  plankton,  Lake 
Erie.  Sweden. 

2.  O.  LACUSTRIS  Chodat,    1897,   p.   296;   1902,  p.   190,  fig. 
103.     Cells  broadly  fusiform,  with  membrane  somewhat  thick- 
ened at  the  subacute  ends,  chromatophore  single  or  in  distinct 
halves,  without  pyrenoid  ;  mother  cell  wall  persistent,  retaining 
the  characteristic  form.     In  plankton,  Lake  Erie.  Europe. 

3.  O.    SOLITARIA   Wittrock   in   Wittr.    and   Nordst.,    Alg. 
Exsicc.,   No.    244;   P.  B.-A.,    No.    1178.     Cells  generally  soli- 
tary,  occasionally  2-4  together,   ellipsoid,    13-35X7-18  /x,  with 
several  chromatophores  ;  membrane  thickish  with  a  tubercular 
projection  at   each    end.     Fig.   44.      Greenland,    Me.,    Mass., 
Conn.,  Cal.,  West  Indies.  Europe,  So.  America. 

Forma  MAJOR  Wille,  1879,  p.  26.  Cells  about  40X22/1*; 
often  in  4-celled  colonies,  60X50  p..  Alaska.  Northern  Europe. 

4.  O.  CRASSA  Wittrock  in  Wittr.  and  Nordst.,  Alg.  Exsicc., 
No.  355.     Cells  usually  in  twos,  ellipsoid  to  fusiform,  I4-23X 
10-18  /A,   with  several   chromatophores  ;    membrane  thin,   only 
slightly  thickened  at  the  ends.     Me.,  Mass.  Europe. 

5.     CHODATELLA  Lemmertnann,  1898,  p.  309. 

Cells  ovoid  or  ellipsoid,  the  membrane  bearing  two  to  many 
setae  not  thickened  at  the  base  ;  chromatophores  one  or  many, 
parietal,  with  or  without  pyrenoid  ;  cells  free  or  contained  in 
the  mother  cell  wall.  Reproduction  as  in  Oocystis. 

This  genus  differs  from  Oocystis  only  by  the  presence  of  the 
setae.  Several  European  species  have  been  described  and  may 
be  expected  here ;  the  following  species,  the  only  one  yet 
reported  here,  is  known  only  from  Lake  Erie. 

C.  CITRIFORMIS  Snow,  1903,  p.  381,  PI.  II,  fig.  VIII.  Cells 
ellipsoidal  with  an  obtuse  projection  at  either  end,  i3-23X8-2O/x; 
chromatophore  single,  with  pyrenoid  ;  setae  slender,  in  whorls 
about  the  projections  at  the  ends  of  the  cells.  Fig.  45.  Lake 
Erie. 

6.     NEPHROCYTIUM  Nageli,  1848,  p.  79. 
Cells  somewhat  curved,  ovoid  or  reniform  ;  asexual  reproduc- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  161 

tion  by  the  division  of  the  contents  of  a  cell  into  2-16  similar 
daughter  cells,  which  remain  enclosed  for  a  lojnger  or  shorter 
time  in  the  persistent  mother  cell  wall ;  chromatophore  covering 
nearly  the  whole  surface  of  the  cell,  with  one  pyrenoid. 

KEY  TO  THE  SPECIES  OF  NEPHROCYTIUM. 

i.     Daughter  cells  2-7  /*  diam.,  3-6  diam.  long.      i.     N.  Agardhianum. 
i.     Daughter  cells  11-22  /j.  diam.,  2  diam.  long.  2.     A^.  Naegelii. 

1.  N.     AGARDHIANUM      Nageli,      1848,      p.     79,     PI.     III.C  \ 

Wolle,  1887,  p.  197,  PI.  CIvXIII,  figs.  12-15,  i?  ;  Wittr.  and 
Nordst.,  Alg.  Exsicc.,  No.  528.  Daughter  cells  2-7  /u,  diam., 
3-6  diam.  long ;  usually  2-4-8  together,  somewhat  spirally 
arranged  within  the  mother  cell  wall  which  may  reach  a  length 
of  60 /A.  Fig.  46.  Me.,  Mass.  J^urope, 

2.  N.  NAEGELII  Grunowin  Rabenhorst,  1868,  p.  62  ;  Wolle, 
1887,  p.  197.     Daughter  cells  11-22  //-diam.,  about  2  diam  long; 
usually  1 6  together,  irregularly  arranged  within  the  mother  cell 
wall.     Me.  Europe. 

7.     TETRAEDRON  Kiitzing,  1845,  p.  129. 

Cells  solitary,  free,  with  parietal  chromatophore  occupying 
the  whole  or  nearly  the  whole  of  the  cell  wall,  with  one  pyre- 
noid ;  of  very  various  form,  either  polyhedric  with  4-many 
angles,  or  flattened,  3-many  angled,  and  in  side  view  more  or 
less  elliptic  ;  angles  from  obtuse  and  rounded  to  very  much  pro- 
longed and  often  branched,  sometimes  repeatedly  and  finely  di- 
vided ;  asexual  reproduction  by  aplanospores,  formed  3-many  in 
a  cell,  developing  into  the  typical  form  of  the  mature  plant 
either  before  or  after  escape  from  the  mother  cell. 

A  genus  containing  species  differing  greatly  in  form,  some  of 
them  very  much  like  stages  in  the  development  of  other  algae  ; 
Hydrodictyon  and  Pediastrum,  for  instance,  produce  "polyhe- 
dric" resting  spores,  and  it  is  probable  that  some  such  forms 
have  been  described  as  species  of  Tctraedron.  Whether  forms 
here  included  will  some  time  have  to  be  removed  for  such  reason 
can  be  decided  only  by  future  investigations.  It  now  seems 
probable  that  some  Tetraedron  species,  at  least,  are  autonomous 
forms,  not  forming  part  of  the  life  cycle  of  any  other  plant. 
Polyedrium  Nageli,  is  a  better  known  name  for  this  genus  than 
Tetraedron  Kiitzing,  and  more  appropriate  ;  but  the  latter  has  a 
priority  of  four  years. 

KEY  TO  THE  SPECIES  OF  TETRAEDRON. 

i.     Cells  flattened,  3  or  more  sided.  2. 

i.     Cells  polyhedric,  but  often  quite  irregular.  10. 


162     TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

2.     Angles  entire  and  unarmed.  3. 

2.     Angles  spinous  or  forked.  6. 

3.     Membrane  finely  granulate-punctate.  5.     T.  punctulatum. 

3.     Membrane  with  a  network  of  ridges.  6.     T,  reticulatum. 

3.     Membrane  smooth.  4. 

4.     Cells  triangular.  2.     T.  muticum. 

4.     Cells  quadrangular.  5. 

5.     Cells  15-21  n  diam.  3.     T.  tetragonum. 

5.     Cells  6-1 1  M  diam.  4.     T.  minimum. 

6.     Angles  prolonged  into  many  fine  divisions.  8.     T.  gracile. 

6.     Angles  mucronate  or  spinous  only.  7. 

7.     Angles  mucronate.  i.     T.  trigonum. 

7.     Angles  spinous.  8. 

8.     Quadrate.  9. 

8.     Polygonal.  10.     T.  angnlosum. 

9.     Regularly  quadrate,  with  short  spines.  7.     7.  quadratum. 

9.     Irregularly  3-  or  4-sided,  with  long  spines. 

9.     T.  quadricuspidatum. 

10.     Angles  unarmed  and  undivided.  n. 

10.     Angles  spinous  or  prolonged  and  divided.  12. 

ii.     Cells  17-26  /j.  diam.  n.     71  pachydermum, 

ii.     Cells  65  fji  or  more  in  greatest  diam.  13.     71  gigas. 

12.     Angles  spinous  but  not  lobed.  13. 

12.     Angles  lobed  or  divided.  14. 

13.     Membrane  thick,  lamellate;    sides  plane  or  slightly  concave  ;  one 

stout  spine  at  each  angle.  12.     7.  regulare. 

13.     Membrane  thin  ;  sides  convex,  unequal;  i  or  2  spines  at  each  angle. 

14.     7.  armatuui. 

14.     Angles  forked  with  rounded  sinus  and  two  sharp  teeth. 

15.     7.  bifurcatum. 

14.     Angles  several  times  lobed  or  forked.  16.     7.  enorme. 

i.  T.  TRIGONUM  (Nag.)  Hansgirg,  1888,  p.  130  ;  Polye- 
drium  trigonum  Nageli,  1848,  p.  84,  PI.  IV.  B,  fig.  i  ;  Reinsch, 
1888,  p.  497,  PI.  IV,  fig.  i.  Cells  triangular,  12-37  M  diam.; 
thickness  6-16  p. ;  sides  slightly  sinuate,  angles  rounded,  mucro- 
nate. Fig.  47.  Mass.,  111.,  Pa.,  Neb.,  Porto  Rico. 

Europe )  Asia. 

Reinsch  gives  four  forms  of  this  species,  distinguished  only  by 
dimensions ;  the  American  plant  comes  under  forma  majus 
Briigger,  with  diam.  of  36  /u.. 

Var.  PUNCTATUM  (Kirchner),  Hansgirg,  1888,  p.  130;  Polye- 
drium  trigoimm  var.  punctatum  Kirchner,  1878,  p.  104;  Wolle, 
1887,  p.  184.  Membrane  granulate,  mucro  small,  papilla-like. 
N.  J.,  Pa.,  Neb.  Europe. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  163 

2.  T.  MUTICUM  (A.  Br.)  Hansgirg,  1888,  p.  131  ;  Polyedrium 
muticum  A.  Braun,  1855,  p.  94;  Reinsch,    1888,  p.  498,  PI.  IV, 
figs.  2,  4  and  6.      Cells  triangular,  13-28  /*  diam.,   7-10  //,  thick  ; 
sides  slightly  sinuate,  angles  rounded,   unarmed.     Mass.,  111., 
Pa.  Europe,  Australia. 

The  Mass,  plant  comes  under  forma  majus  Reinsch  ;  sides 
slightly  convex,  angles  rounded  ;  23-28  /*  diam.,  10-11  p.  thick  ; 
the  111.  plant  under  forma  punctulatum  Reinsch  ;  sides  slightly 
concave,  membrane  finely  punctate,  diam.  18-21  /*. 

In  general  form  and  dimensions  this  species  is  much  like 
T.  trigonum,  but  has  more  rounded  angles  and  lacks  the  spine 
or  mucro  characteristic  of  T,  trigonum. 

3.  T.  TETRAGONUM  (Nag.)    Hansgirg,    1889,  p.   18 ;  Polye- 
drium tetragonum  Nageli,  1848,  p.  84,  PI.  IV. B,  fig.  2  ;  Reinsch, 
1888,  p.  499,  PI.  IV,  fig.  10  a  and  b;  P.  trigonum  var.  tetrago- 
num Wolle,   1887,  p.   184,    PI.  CLIX,  figs.  7-10.     Cells  quad- 
rangular, sides  slightly  sinuate,  angles   rounded.      Diam.   15- 
21 //..     Mass.,  111.,  Pa.,  Neb.       Europe,  Australia,  So.  America. 

Characterized  by  the  squarish  outline,  with  rounded  angles 
and  slightly  concave  sides,  with  no  projections  of  any  kind ;  it 
varies  slightly  as  to  dimensions,  but  not  otherwise. 

4.  T.  MINIMUM  (A.  Br.)  Hansgirg,  1888,  p.  131  ;  Wittr.  and 
Nordst.,    Alg.    Exsicc.,    No.    1573;    Polyedriiim    minimum  A. 
Braun,    1855,   p.   94;    Reinsch,    1888,  p.  499,   PI.   IV,  fig.  2; 
Wolle,  1887,  p.  185,  PI.  CLIX,  figs.  28-34.     Cells  quadrangu- 
lar,   6- 1 1    /A    diam.,    sides    rather    deeply    emarginate,    angles 
rounded;    in  side  view  elliptic,  3-6  p.  thick.     Me.,  Pa. 

Europe,  Asia,  So,  America. 

Resembles  a  small  T.  tetragonum,  but  according  to  Reinsch, 
is  not  connected  by  intermediate  forms. 

5.  T.    PQNCTULATUM    (Reinsch)    Hansgirg,    1889,    p.    18 ; 
Polyedrium  punctulatum  Reinsch,    1888,    p.   500,   PL  IV,  fig.  8. 
Cells  quadrangular,  18-21X21-30  //. ;  in  side  view  rhomboidal, 
15-18  /A  at  the  thickest ;  sides  straight  or  slightly  and  irregularly 
repand,  angles  obtuse ;    membrane  thin,    not   lamellate,  finely 
granular-punctate.     Mass.  Europe. 

Our  plant  is  forma  rectangulare  Reinsch,  with  cells  longer 
than  wide. 

6.  T.  RETICULATUM  (Reinsch)  Hansgirg,  1889,  p.  18  ;  Polye- 
dtiuin  reticulatum  Reinsch,   1888,  p.  498,  PL  IV,  fig.  3.     Cells 
triangular,  26-30  /u.  diam.  ;  with  equal  and  nearly  straight  sides, 


1 64  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

angles  somewhat  rounded  ;  membrane  thin,  covered  with  a  net- 
work of  very  delicate  ridges.     Cuba.  Europe,  Africa. 

7.  T.  QUADRATUM  (Reinsch)  Hansgirg,  1889,  p.  18;  Polye- 
drium  quadratum  Reinsch,    1888,  p.  499,  PI.  IV,  fig.  7.     Cells 
regularly   quadrate,   sides   straight  or  slightly   convex,    angles 
obtuse,  each  with  a  single  spine  ;  membrane  rather  thick,  dis- 
tinctly of  two  layers;  diam.  17-34  ft;  membrane  2-4.5  ft  thick. 

The  type  occurs  in  Europe ;  we  have  only  forma  minus 
acutum  ;  cell  17-18  p.  diam.;  angles  subacute ;  membrane  only 
indistinctly  lamellate.  111. 

8.  T.  GRACILE  (Reinsch)  Hansgirg,  1889,  p.  19  ;  Polyedrium 
gracile  Reinsch,  1888,  p.  502,  PI.  VII,  fig.  i.     Cells  four-angled, 
sides  equal,  emarginate  or  deeply  and  obtusely  incised,  angles 
prolonged,   three   times   forked,    divisions   divergent,    ultimate 
divisions  very  slender,  acute ;  prolongations  from  the  angles  as 
long  as   the    diam.    of  the    cell;    cell    in    side  view   narrowly 
elliptic,  with  prolonged  ends;  total  diam.  of  cell  35-46 /x ;  dis- 
tance between  centers  of  sides  18-20  ft.     Mass. 

Var.  tenue  (Reinsch)  nov.  comb.  ;  Polycdrium  gracile  we.  tenue 
Reinsch,  1888,  p.  502,  PI.  VII,  fig.  la.  Sides  very  deeply  in- 
cised, lobes  of  the  angles  in  all  orders  very  slender.  Mass. 

9.  T.  QUADRICUSPIDATUM  (Reinsch)  Hansgirg,  1889,  p.  18  ; 
Polyedrium  quadric2ispidatum  Reinsch,  1888,  p.  500,  PI.  VI,  fig. 
2.     Cells  50-95X36-63  ft,  with  3  or  4  unequal  sides,  convex  or 
concave,  each  angle  ending  in  a  long,  acute,  stout  spine,  13-14^ 
long ;  membrane  th'in,  thickened  at  the  angles  ;    cells  in  side 
view  narrowly  elliptic,  with  attenuate,  spinous  ends.     Mass. 

Europe. 

Quite  irregular  in  outline  of  the  cell,  but  characterized  by  the 
four  stout  spines ;  in  Mass,  is  reported  the  type,  also  forma 
inaequale  Reinsch,  which  seems  to  differ  only  in  having  spines 
of  unequal  length. 

10.  T.  angulosum  (L/arsen)  nov.  comb.  ;  Polyedrium  angu- 
losum  L/arsen,  1904,  p.   104,  fig.  8.     Cells  more  or  less  irregu- 
larly  polygonal,  with   rounded   angles,    each   with   two   short 
spines.     Greenland. 

Possibly  identical  with  Polyedrium  irregulare  Reinsch,  1888, 
p.  508,  PI.  VII,  fig.  3. 

11.  T.    PACHYDERMUM    (Reinsch)  De  Toni,   1889,  p.  603; 
Polyedrium  pachydcrmum   Reinsch,  1888,   p.   504,   PL  V,  fig.  2. 
Cells  6-8-angled,  17-26  ft  diam.,  sides  usually  equal  and  sym- 
metrical,  emarginate,    angles   rounded,    obtuse ;    in   side  view 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  165 

elliptic ;  membrane  very  thick,  up  to  5  /*,  of  2-many  lamellae. 
Mass.  I  Europe. 

The  type  is  not  reported  with  us,  but  only  forma  minus  and 
forma  leptodcrmum  ;  both  forms  have  cells  17-19  p-  diarn.,  mem- 
brane thinner  and  less  lamellate  than  in  the  type  ;  from  Reinsch's 
description  and  figures  it  is  not  easy  to  find  any  distinction  be- 
tween the  two  forms. 

12.  T.  REGULARS  Kiitzing,  1845,  p.  129;  Polyedrium  tetrae- 
dn'ciim  Niigeli,  1848,  p.  84,   PL  IV. B,  fig.  3.     Cells  tetraedric, 
usually  14-50  p.  diam.,  sides  plane  or  slightly  concave,  angles 
obtuse,   each  with   a  short  spine  ;  membrane   thick,   distinctly 
lamellate. 

Many  varieties  and  forms  have  been  described  ;  we  have  only 
var.  longispinum  (Reinsch)  De  Toni,  1889,  p.  605  ;  Polyedrium 
tetraedricum  var.  longispinum  Reinsch,  1888,  p.  506,  PI.  V,  fig. 
ra  ;  P.B.-A.,  No.  1466.  Spines  longer,  up  to  half  the  length 
of  a  side.  Mass.  Europe. 

13.  T.  GiGAS  (Wittr.)  Hansgirg,    1888,   p.   131  ;  Polyedrium 
gigas  Wolle,  1887,  p.  184,  PL  CLJX,  figs.  11-14;  P.  tumidulum 
var.  rotundatum  Reinsch,    1888,  p.  506,   PL  VI,  fig.  3a.     Cells 
irregularly  5-6-angled,   65-75X35-45  M.   sides  concave,   angles 
unarmed.     Me.,  Mass.,  Pa.  1  tin-ope.  New  Zealand. 

14.  T.   ARMATUM   (Reinsch)  De  Toni,    1889,  p.  611;  Polye- 
drium armatum  Reinsch,   1888,  p.   508,   PL  VI,  fig.   i.     Cells 
22-31  //.  diam.,  with  irregular,  rounded  sides,  and  3  or  4  incon- 
spicuous rounded  angles,  each  with  i  or  2  stout  spines,  5-8  /u, 
long  ;  membrane  rather  thick,  not  lamellate.     Mass.        Europe. 

Beside  the  type  we  have  var.  minus  Reinsch,  1888,  p.  508, 
PL  VI,  fig.  ic  ;  Cells  22  /x  diam.,  flattened,  with  3  nearly 
straight  sides,  and  2  spines  at  each  angle. 

15.  T.    BIFURCATUM    (Wille)    Lagerheim,    i893a,    p.    160 ; 
Polyedrium  trigonum  var.   bifurcatum  Wolle,  1887,  p.    184,  PL 
CL1X,  figs.  15-18.     Cells  tetraedric,  about  30 /*  diam.,  3  or  4- 
angled,  angles  bifurcate,  with  sharp  tips.     Cuba,  Porto  Rico. 

So.  America. 

16.  T.  ENORME  (Ralfs)  Hansgirg,  1888,  p.  132;  Polyedrium 
enonnc  Wolle,  1887,  p.  184,  PL  CLJX,  figs.  19-23.     Cells  irreg- 
ularly tetraedrical,  generally  25-45  //,  diam.,  angles  prolonged, 
colorless,    often   deeply   lobed,    sometimes    repeatedly    forked ; 
divisions  mucronate.     Me.,  Pa.  hurope. 

With  many  varieties  and  forms,  based  on  dimensions  and  on 


1 66          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

the  number  and  size  of  the  angular  projections ;    all  passing 
into  each  other  without  any  sharp  line. 

8.     THAMNIASTRUM  Reinsch,  1888,  p.  513. 

Cells  solitary,  free,  composed  of  six  branches  issuing  at  right 
angles  from  a  common  center,  di-trichotomously  divided  ;  ulti- 
mate divisions  acute,  spreading.  Only  one  species. 

T.  CRUCIATUM  Reinsch,  1888,  p.  513,  PI.  VIII,  fig.  3.  Char- 
acters of  the  genus;  ultimate  divisions  100-200,  1-2  ^  diam. 
Fig.  49.  Mass. 

Nothing  being  known  as  to  the  reproduction  of  the  plant, 
which  has  not  been  reported  since  its  original  discovery,  its 
position  here  is  provisional  only,  and  based  on  habit  characters. 
9.  CERASTERIAS  Reinsch,  1867,  p.  68. 

Cells  solitary,  free,  consisting  of  elongate  rays  from  a  com- 
mon center,  without  distinct  central  body  ;  otherwise  as  in  Tet- 
raedron. 

Doubtfully  distinct  from  Tetraedron,  differing  only  in  the 
greater  development  of  the  projections  and  consequent  reduc- 
tion of  the  main  body. 

KEY  TO  THE  SPECIES  OF  CERASTERIAS. 

i.     Rays  acute.  i.     C.  raphidioides. 

i.     Rays  obtuse.  2.     C.  stattrastroides. 

1.  C.  RAPHIDIOIDES  Reinsch,    1867,  p.   68,    PI.   V,   fig.    i  ; 
1888,  p.  511.     Rays  3-8,  subulate,  acute.     Fig.  48.    With  many 
forms,  of  which  we  have  two. 

Var.  INCRASSATUM  Reinsch,  1888,  p.  512,  PL  VIII,  fig.  4  L 
Cell  consisting  of  4  or  5  rays,  2.5-3X10-15  /n,  3  or  4  arranged  in 
a  whorl  at  one  end  of  the  other  ray  ;  or  2  or  3  in  a  whorl  about 
one  continuing  the  direction  of  the  single  ray,  the  single  ray 
acuminate,  other  rays  equal  with  rounded  or  sometimes  acumi- 
nate ends.  Mass.  Europe,  Africa. 

Var.  INAEQUALE  Reinsch,  1888,  p.  512,  PI.  VIII,  fig.  4,  a-c. 
Single  ray  10-15X2-3  n,  with  acute  lower  end,  at  upper  end  with 
3  similar  acute  rays,  and  3  rays  of  about  half  the  length,  with 
obtuse  ends.  Mass.  Europe,  Africa. 

2.  C.  STAURASTROIDES  W.   and  G.   S.  West,  1895,  p  268, 
PI.  XIV,  fig.    16.      Rays  four,   elongate,   attenuate,    minutely 
granulate,  apex  obtuse;  thickness  of  central  portion,  9-10  /*; 
total  diam.,  30-35  p..     On  trees.     Dominica. 

Polyedrium  minutum  L,arsen,  p.  104,  fig.  7,  would  seem  to  be- 
long here,  apparently  intermediate  between  the  two  species. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  167 

10.     SCHIZOCHLAMYS  A.  Braun  in  Ku'tzing,  1849,  p.  891. 

Cells  spherical  or  ellipsoid,  irregularly  distributed  through  the 
colorless  gelatine,  free  floating  or  attached  to  water  plants ; 
chromatophore  filling  the  cell,  without  pyrenoid  ;  cell  dividing 
into  two  daughter  cells,  the  mother  cell  wall  remaining  in  2  or  4 
pieces,  about  the  new  cells.  Only  one  species. 

S.  GELATINOSA  A.  Braun  in  Kiit/.ing,  1849,  p.  891  ;  1856, 
PI.  LJI ;  P.  B.-A.,  No.  369.  Forming  an  irregular  mass,  up  to 
10  cm.  long,  pale  or  yellowish  green  ;  cells  globose  or  ellipsoid, 
11-14  M  wide,  sometimes  arranged  by  2  or  4.  Fig.  50.  Me., 
Mass.,  Alaska,  Cal.  Europe. 

Much  like  a  Tetraspora,  but  not  inembranaceous,  and  distin- 
guished by  the  persistent  pieces  of  the  mother  cell  wall,  several 
generations  of  which  may  be  found  enclosed  within  the  oldest, 
ii.     ELAKATOTHRIX  Wille,  1898,  p.  302. 

Cells  ovoid  or  fusiform,  with  parietal  chromatophore  covering 
all  the  wall  except  at  the  ends,  with  a  large  pyrenoid  ;  in  a  gen- 
eral gelatinous  sheath  ;  cell  dividing  by  a  cross  wall,  the  daugh- 
ter cells  maintaining  a  longitudinal  arrangement  for  a  longer  or 
shorter  time. 

E.  AMERICANA  Wille,  1899,  p.  150;  P.  B.-A.,  No.  607; 
Pusola  viridis  Snow,  1903,  p.  389,  PI.  II,  fig.  VI.  Cells  ovoid 
or  fusiform,  12-25X6-15  /*,  dividing  across  the  middle,  the 
daughter  cells  growing  out  obliquely,  effacing  the  original  lon- 
gitudinal order  ;  the  gelatinous  sheath  in  the  form  of  a  laciniate, 
anastomosing  thallus,  attached  to  various  plants  and  reaching  a 
length  of  several  cm.;  later  forming  floating  masses  of  indefi- 
nite form.  Fig.  51.  Conn.,  Lake  Erie. 

12.     HORMOTILA  Borzi,  1883,  p.  99. 

Cells  spherical,  ovoid  or  ellipsoid,  with  one  pyrenoid;  either 
arranged  2-4-8-16  together  in  a  wide,  more  or  less  firm,  often 
concentrically  lamellate  gelatinous  mass,  which  may  form  a  con- 
siderably extended  stratum  ;  or  distributed  at  intervals  along 
colorless,  branching,  cylindrical,  gelatinous  bands.  Asexual 
reproduction  by  zoospores,  formed  in  ovoid  sporangia,  much 
larger  than  the  vegetative  cells  ;  zoospores  8  or  more  in  a  spor- 
angium, ovoid  or  ovoid-oblong,  with  red  stigma,  and  prolonged 
to  a  point  with  two  cilia  ;  escaping  through  a  lateral  opening. 
Only  one  species. 

H.  MUCIGENA.  Borzi,  1883,  p.  99,  Pis.  VIII  and  IX;  P. 
B.-A.,  No.  1218.  Cells  4-i2/xdiam.,  sporangia  to  30  ^  diam., 
zoospores  3-5X1-2.5  //, ;  mass  reddish  or  bluish.  On  woodwork, 
etc.,  in  standing  fresh  water.  Fig.  52.  Cal.  Europe. 


168  TUFTS  COLLEGE;  STUDIES,  VOL.  II,  No.  3 

13.     SCENEDESMUS  Meyen,  1829,  p.  774. 

Colonies  free,  of  2-8  cells,  in  one  row,  or  in  two  rows  side  by 
side  ;  ovoid  or  with  pointed  ends,  all  smooth  or  all  or  part  with 
spines  or  horns  ;  chromatophore  nearly  filling  the  cell,  with  one 
pyrenoid ;  division  either  by  longitudinal  walls  through  each 
cell,  or  also  by  a  wall  through  the  length  of  a  colony,  dividing 
each  cell  across  the  middle ;  daughter  cells  escaping  either 
singly  or  united  in  colonies ;  the  free  cells  often  differing  con- 
siderably in  form  from  the  normal  colony  cells. 

Common  in  gatherings  of  miscellaneous  algae  from  still  water; 
in  such  collections  made  in  warm  weather  one  is  almost  certain 
to  find  colonies  of  Scenedesmus ;  but  it  is  unusual  to  find  them 
constituting  the  bulk  of  a  collecting. 

KEY  TO  THE  SPECIES  OF  SCENEDESMUS. 

i.     Ends  of  cells  obtuse  or  rounded.  2. 

i.     Ends  of  cells  acute.  2.     S.  obliqutis. 

2.     Terminal  cells  of  series  with  long  projections. 

5.  S.  quadricanda. 

2.     All  cells  similar.  3. 

3.     Cells  without  teeth  or  spines.  i.     S.  bijuga. 

3.     Cells  with  teeth  or  spines.  4. 

4.     Cells  covered  with  minute  spines.  4.     S.  Hyslrix. 

4.     Cells  with  denticulate  ends.                                  3.  5.  denticulatus. 

1.  S.  BIJUGA  (Turp.)  Wittr.,    Nordst.    and   Lagerh.,    Alg. 
Exsicc.,    No.    1567;    P.   B.-A.,    No.    1220;    5".  obtusus  Wolle, 
1887,  p.  173,  PI.  CL,VI,  figs.  22-24.     Colonies  of  4-8  cells;  cells 
oblong-ellipsoid    or    ovoid,    with   rounded   ends,    7-18X4-7   M> 
arranged  in  a  single  or  double  row.     Greenland,  Me.,  Mass., 
Neb.,  Cal.  •  Europe. 

Var.  ALTERNANS  (Reinsch)  Hansgirg,  1886,  p.  114;  P. 
B.-A.,  No.  1181.  Cells  broader  than  in  the  type,  in  two  rows, 
alternately  placed  ;  merely  a  form,  hardly  worthy  of  a  name. 
Porto  Rico,  Cal.  Europe. 

Var.  flexuosus  (Lemmermann)  nov.  comb.  ;  5.  bijugatus  var. 
flexuosus  Lemmermann,  1898,  p.  191,  PI.  V,  fig.  i  ;  Snow,  1903, 
p.  375,  PI.  I,  fig.  IV.  Cells  8-16-32  in  a  single  series,  io-2oX 
5-8  /A.  L,ake  Erie.  l-'.tirope. 

2.  S.  OBLIQUUS  (Turp.)  Kiitzing,    1833,  p.  609;    P.  B.-A., 
No.  1320;  S.acutus  Nageli,  1848,  PI.  V.  A,  fig.  3.     Colonies  of 
4-8  cells,  cells  fusiform  with  acute  ends,  usually  in   a  single 
series,  5-27X3-9  /"••     Fig.    53.     Me.,    Mass.,    Neb.,    Barbados, 
Cal.  Europe. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA     169 

Var.  DIMORPHUS  (Turp.)  Hansgirg,  1886,  p.  116;  6*.  acutus 
var.  dimorphus  Rabenhorst,  1868.  p.  64;  6".  dimorphus  P.  B.-A., 
Nos.  1020  and  1319.  Cells  united  in  a  single  series,  end  cells 
crescent-shaped,  median  cells  straight.  Me.,  Mass.,  Neb.,  Cal. 

Europe. 

3.  S.  DENTICULATUS  L,agerheim  var.  LINEARIS  Hansgirg, 
1886,  p.  268.     Colonies  of  4-8  cells,  in  a  nearly  straight  line, 
4-5  p.  wide,  to    15  /u.   long  ;  each   end  with  two  minute  teeth. 
Greenland,  Mass.,  Trinidad,  Washington.  Europe. 

The  type  with  ovoid  or  oblong  cells,  7-8X5-11  /",  occurs  in 
Europe,  but  has  not  yet  been  reported  from  America. 

4.  S.  HYSTRIX  L-agerheim,  1882,  p.  62,  PL  II,  fig.  18.     Col- 
onies 2-8-celled  ;  cells  oblong  cylindric,  straight  with  rounded 
ends,  in  a  single  series,  12-18X3-6  /u.;  membrane  with  numer- 
ous short  spines.     Porto  Rico.  I^urope. 

5.  S.  QUADRICAUDA  (Turp.)  Brebisson,    1835,  p.  66  ;  Ralfs, 
1848,  p.    190,    PL  XXXI,   fig.  12;  6*.  caudatus  Wolle,  1887,  p. 
172,  PL    CLVI,  figs,    ii  and    12;  P.  B.-A.,   No.   1321.     Colo- 
nies of  2-8  cells,  oblong-cylindric  with  rounded  ends,  9-33X3-12 
/x,  arranged  in  a  single  series  or  in  two  alternating  rows  ;  end 
cells  usually  with  long,  filiform  projections  ;  intermediate  cells 
with  rudimentary  or  no  projections.     Greenland,  Me.,  N.  H., 
Mass.,  Ohio,  Neb.,  Wyo.,  Jamaica. 

Europe,  Asia,  New  Zealand. 

A  very  common  species,  the  description  above  applying  to  the 
typical  form  ;  a  number  of  varieties  and  forms  have  been  de- 
scribed, of  which  we  have  probably  a  good  part  ;  the  four  fol- 
lowing forms  occur  commonly  :  — 

Forma  TYPICUS  Kirchner,  1878,  p.  98.  Projections  on  ter- 
minal cells  only, 

Forma  SETOSUS  Kirchner,  1878,  p.  98.  Projections  on  some 
median  cells. 

Forma  HORRIDUS  Kirchner,  1878,  p.  98.  Projections  on  all 
cells. 

Forma  ABUNDANS  Kirchner,  1878,  p.  98;  Wittr.  &  Nordst., 
Alg.  Exsicc.,  No.  525.  Terminal  cells  with  median  as  well  as 
terminal  projections. 

Var.  ELLIPTICUS  W.  &.  G.  S.  West,  iSgsa,  p.  83,  PL  V,  fig. 


*Among  the  doubtful  forms  of  the  genus  must  be  reckoned  S.  rotunda- 
tits  Wood,  1872,  p.  91  ;  S.  polymorphus  Wood,  1872,  p.  91;  S.  antennatus 
var.  rectus  Wolle,  1887.  p.  172,  PL  CLVI,  figs.  16  and  17. 


1 70          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

6;  G.  S.  West,  1905,  p.  287.  Cells  perfectly  ellipsoid,  about 
12X5  p-,  4  in  a  single  series,  2  strong  spines,  curved  outward,  on 
each  terminal  cell ;  the  two  median  cells  with  one  such  spine 
each,  in  opposite  directions.  Barbados.  Madagascar. 

14.     CRUCIGENIA  Morren,  1830,  p.  404. 

Colonies  free,  of  4-8-16,  rarely  more  cells,  lying  in  the  same 
plane,  with  perforations  at  places  where  the  cells  have  divided 
and  separated  from  each  other ;  cells  with  parietal  chromato- 
phore  and  one  pyrenoid,  smooth  or  with  prominences,  touching 
at  the  middle  or  at  the  outer  end,  and  enclosed  in  more  or  less 
plentiful  gelatine ;  asexual  reproduction  by  the  division  of  a 
cell  into  4  daughter  cells,  arranged  like  the  mother  colony. 
Fresh  water  plankton  algae. 

KEY  TO  THE  SPECIES  OK  CRUCIGENIA. 

i.     Cells  apiculate.  3.     C.  apiculata. 

i.     Cells  not  apiculate.  2. 

2.     Cells  ovoid,  oblong,  or  somewhat  curved,  4-32  in  a  colony. 

i.     C.  rectangularis. 
2.     Cells  rhomboidal,  4  in  a  colony.  2.     C.  crucifera. 

1.  C.  RECTANGULARIS  (A.  Br.)  Gay,  1891,  p.  ioo,  PL  XV, 
fig.  151  ;  Wittr.  and  Nordst.,fAlg.  Exsicc.,  Nos.  53,  171.    Cells 
4-6X5-7  /"•,  4-8-16-32  in  a  colony,   13-55  ^  square,  with  rounded 
angles ;   always  in  groups  of  4,  with  a  quadrangular  opening 
in  the  center  of  the  group ;   fragments  of  the  mother  cell  wall 
sometimes  persistent ;  cells  oval  or  oblong,  touching  near  the 
outer  end,  or  curved  and  touching  near  the  middle.     Fig.  54. 
Greenland,  Mass.  Europe,  Asia. 

2.  C.   crucifera   (Wolle)  nov.    comb.;   Staurogenia-crutiata 
Wolle,  1887,  p.  171,  PI.  CI/VII,  figs.  9-n.     Cells  rhomboidal, 
equilateral, -with  incurved  sides  and  rounded  angles,  four  form- 
ing a  colony  of  the  same  form  as  the  individual  cell;    "cells 
with  a  cruciform  marking  on  the  surface."     Wolle.     Pa.  • 

The  figures  given  by  Wolle  are  very  rudimentary,  but  seem 
to  indicate  a  distinct  species.  The  cruciform  marking  of  the 
cells  is  probably  due  to  cell  division  in  process. 

3.  C.  APICULATA    (L-emmermann)    Chodat,    1902,     p.   207  ; 
Snow,    1903,    p.    376,    PL    I,  fig.  V.      Cells   elongate,    ovoid, 
or  by  pressure  at  one  end  subtriangular,   5-8X3-5  p-,  with  an 
apiculum  at  one  end,  sometimes  at  each  end ;  united  in  fours  or 
multiples  of  four  in  a  flat,  more  or  less  regularly  rectangular 
plate. 

In  reproduction  each  cell  divides  to  form  4  daughter  cells, 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  171 

which  often  remain  attached  by  the  general  gelatinous  envelop, 
forming  a  rectangular  plate,  which  may  measure  as  much  as 
150  fj.  on  a  side,  and  in  which  the  number  of  cells  is  normally 
some  power  of  four.  Lake  Erie.  Europe. 

15.     SELENASTRUM  Reinsch,  1867,  p.  64. 
Cells  crescent  or  sickle-shaped,  with  parietal  chromatophore 
and  no  pyrenoid  ;  usually  united  in  families  of  4-8-16  ;  asexual 
reproduction  by  division  of   cell  into  4  daughter  cells,  which 
arrange  themselves  like  the  parent. 

KEY  TO  THE  SPECIES  OF  SEI.ENASTRUM. 

i.     Cells  less  than  10  /j.  from  tip  to  tip.  i.     5.  minututn. 

i.     Cells  16  fj.  or  more  from  tip  to  tip.  2.     S.  Bibraianutn. 

1.  S.  MINUTUM  (Nag.)  Collins,  P.  B.-A.,  No.  1422;  Raph- 
idium  mimttum  Nageli,    1848,  p.   82,   PI.  IV.C,  fig.  2.       Cells 
crescent-shaped,  usually  uniformly  curved  ;  7-9  p,  from  tip  to 
tip  to  tip,  2-3  p.  wide  at  middle  ;  cells  rarely  continuing  united, 
usually  free.     Fig.  55.     Mass.  Europe. 

2.  S.  BIBRAIANUM  Reinsch,  1867,  p.  64,   PI.  IV,  fig.  2  ;   P. 
B.-A.,  No.  1317.     Cells   crescent-  or  sickle-shaped,  uniformly 
curved  or  with  tips  straight ;  families  of  four  cells  joined  at  the 
middle  of  the  convex  side  of  each  cell ;  these  four-celled  families 
often   united    in  subspherical   colonies  of   8  or  1 6  cells ;  cells 
16-23  p.  long,  5-8  p.  wide  at  thickest  part.     Me.,  Mass.,  Wash. 

Europe. 
16.     KIRCHNERIELLA  Schmidle,  1893,  p.  83. 

Cells  arcuate  or  crescent-shaped,  uninucleate,  with  parietal 
chromatophore  and  usually  one  pyrenoid,  loosely  aggregated 
without  apparent  order  in  a  large  gelatinous  mass  ;  asexual  re- 
production by  division  into  4  or  8  daughter  cells. 

K.  LUNARIS  (Kirchner)  Moebius,  1894,  p.  331  ;  Chodat,  1902, 
p.  202,  figs.  121  and  122.  Cells  crescent- shaped,  with  rounded 
ends,  3-5 /x  diam.  at  middle,  6-10 /u,  long.  Fig.  56.  Me.,  Mass. 

Europe. 

Var.  DIANAE  Bohlin,  1897,  p.  20,  Pi.  I,  figs.  28-30;  P.  B.-A., 
No.  1513.  Cells  more  curved,  tips  acute  and  often  not  in  the 
same  plane.  Me.,  Mass.  So.  America. 

The  'genus  differs  from  Sclenastrum  by  the  absence  of  any 
definite  arrangement  of  the  individual  cells,  and  by  the  presence 
of  an  ample  enclosing  mass  of  gelatine.  Both  type  and  variety 
of  K.  lunaris  occur  among  water  plants  in  ponds,  etc. 

17.     COE^ASTRUM  Nageli  in  Kiitzing,  1849,  p.  195. 

Cells   spherical  to  polygonal,   uninucleate,  with  bell-shaped 


172  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

chromatophore  and  one  pyrenoid  ;  asexual  reproduction  by  suc- 
cessive division  into  2-32  cells,  escaping  by  the  splitting  of  the 
mother  cell  wall  into  halves,  still  attached  in  part ;  cells  remain- 
ing separate  or  uniting  into  a  colony,  spherical  or  sub-spheri- 
cal, solid  or  hollow,  joined  by  the  gelatinous  outer  coating  of 
the  cell  wall.  Widely  distributed  fresh  water  plankton  algae  ; 
here  arranged  chiefly  according  to  Senn,  1899,  which  is  a  care- 
ful revision  of  the  genus. 

KEY  TO  THE  SPECIES  OF  COELASTRUM. 
i.     Cells  united  by  arm-like  processes  from  the  membrane. 

5.     C.  reticii lain  in. 

I.     Cells  in  contact  or  united  by  quite  short  processes.  2. 

2.     Cells  with  a  short,  free,  external  projection.  3. 

2.     Cells  without  external  projection.  4. 

3.     Interspaces  about  equal  to  diam.  of  cell.  3.     C.  proboscideuin. 

3.     Interspaces  much  smaller  than  diam.  of  cell.        4.     C.  cambricitm. 

4.     Cells  spherical  or  slightly  elongate  ;  interspaces  very  small. 

I.     C.  microporum. 
4.     Cells  ovoid,  mutually  compressed;  interspaces  \-\  cell  diam. 

2.     C.  sphaericum. 

1.  C.  MICROPORUM  Nageli  in  A.  Braun,  1855,  p.  70;  Senn, 
1899,  p.  53.  PI.  II,  figs.  11-17  J  -P-  B.-A.,  No.  1423.     Cells  6-16 
/A  diam.,  spherical  or  slightly  elongate  and  laterally  compressed, 
united  by  the  gelatinous  surfaces  ;    interspaces  much  smaller 
than  the  cell  diam.  ;  colony  40-55  /*  diam.     Mass.,  Pa.,  Porto 
Rico.  Europe. 

2.  C.   SPHAERICUM  Nageli,    1848,   p.  98,    PI.  V.C.,   fig.    i  ; 
Wittr.,   Nordst.  and  L,agerh.,  Alg.  Exsicc.,  No.    1241.     Cells 
4-20 p.  diam.,  ovoid,  mutually  much  flattened,  deformed  mostly 
at  the  outer  pole ;  intervals  between  the  cells  about  equal  to 
half  the  cell  diam.  ;  colony  20-90  p.  diam.     Cuba.  Europe. 

3.  C.  PROBOSCIDEUM  Bohlin,  i897a,  p.  33,  PI.  II,  figs.  19-22  ; 
Senn,    1899,   p.    59,   PI.    II,   figs.    18-22  ;    Wittr.,    Nordst.   and 
Lagerh.,  Alg.  Exsicc.,  No.  1240;    C.  microporum  Wolle,  1887, 
p.    170,    PL  CLVI,  figs.   1-3,  not  of  Nag.     Cells  7-40  /u.  diam., 
varying  in  form,  but  usually  more  or  less  angular,  and  with  the 
outer  pole  prolonged  in  some  form,  and  crowned  with  a  gelat- 
inous thickening,   varying  much  in  size  and  shape  ;    colonies 
usually  of  2-16  cells  in  a  loose  network  with  relatively  large 
open  spaces.     Greenland,  Me.,  Mass.,  N.  J. 

Europe,  So.  America. 

C.  microporum  var.  speciosum  Wolle,  1887,  p.   170,   PI.  ClyVI, 
fig.    4,    with  projections   like    C.  proboscideum ,   but  with  cells 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  173 

united  by  gelatinous  filaments,  is  difficult  to  locate,  and  may 
possibly  belong  in  another  genus.  Nothing  can  be  determined 
until  the  plant  is  rediscovered. 

4.  C.  CAMBRICUM  Archer,  1868,  p.  65  ;   ?Wolle,  1887,  p.  170, 
PI.  CL/VI,  fig.  5.     Cells  6-12  p.  diam.,  angular  and  somewhat 
lobed,  with  a  truncate  projection  at  the  middle  ;    interspaces 
quite  small ;  colony  20-70  p.  diam.     Fig.  57.     Mass.         l^urope. 

5.  C.   RETICULATUM  (Dangeard)  Senn,   1899,  p.  40,  fig.   r. 
Cells  2-4-8-16,  6-24  fj,  diam.,  connected  with  each  other  by  more 
or  less   numerous,   arm-like   prolongations  of  the   membrane, 
forming  a  basket-like  network  about  the  spherical  or  spheroidal 
colony,  which  may  continue  intact  for  some  time  after  the  for- 
mation of  daughter  cells  in  each  cell  of  the  colony.     Lake  Erie. 

Europe. 
18.  SORASTRUM  Kiitzing,  1845,  p.  144. 

Colonies  unattached,  solid,  composed  of  4-32  cordate,  cune- 
ate,  reniform,  or  suboviform  cells,  which  are  united  at  the  center 
of  the  colony  by  short  stipes,  and  radially  arranged  ;  cells  with 
1-4  spines,  projecting  from  the  larger  (exte/nal)  end  of  each 
cell ;  chromatophore  single,  with  one  pyrenoid  ;  asexual  repro- 
duction by  the  colony  breaking  up  into  its  individual  cells, 
which  then,  either  at  once  or  after  division,  develop  each  a  new 
colony,  which  bursts  through  the  membrane. 

Differs  from  Coelastrum  chiefly  in  the  shape  of  the  cells,  and 
in  that  the  colony  breaks  up  before  the  development  of  the  new 
colonies  begins  ;  but  the  reproduction  is  not  fully  understood. 

KEY  TO  THE  SPECIES  OF  SORASTRUM. 
i.     Outer  angles  of  cells  rounded,  each  with  2  spines. 

1.  5".  spinulosuni. 
i.     Outer  angles  of  cells  ending  each  in  a  short,  conical  point. 

2.  S.  bidentatuin. 

1.  S.  SPINULOSUM  Nageli,    1848,   p.   99,   PI.   V.D ;    Wolle, 
1887,  p.  171,  PI.  CL/VI,  figs.  6-10.     Colony  23-60 /u.  diam.;  cells 
8-32,  cuneate,  outer  end  somewhat  emarginate  or  subcordate, 
and  with  two  pairs  of  spines  about  15  /x.  long  on  each  cell.     Fig. 
58.     Me.,  Mass.,  Neb.,  Washington,  Porto  Rico.  Europe. 

2.  S.   BIDENTATUM   Reinsch,    1867,   p.   86,   PI.   IV,   fig.    i. 
Colony  globose,  about  30  ^  diam.,  of  8-16  cells,  wedge-shaped, 
elliptic  in  surface  view,  with  a  deep  sinuate   incision  in   the 
outer  edge,  the  angles  slightly  prolonged  and  somewhat  acute. 
Porto  Rico.  Europe. 

19.     DICTYOSPHAERIUM  Nageli,  1848,  p.  72. 
Cells   originally  spherical,   with   cup-shaped   chromatophore 


174  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

and  one  pyrenoid  ;  repeatedly  dividing  by  twos  and  fours,  the 
last  generation  being  at  the  apices  of  dichotomous,  gelatinous 
strands,  radiating  from  the  position  of  the  original  cell,  and  be- 
ing part  of  the  cell  wall  left  behind  in  the  course  of  the  daughter 
cells  outward  ;  the  whole  enclosed  in  a  general  gelatinous  mass; 
asexual  reproduction  by  the  transformation  of  a  cell  into  a  bicil- 
iate  zoospore,  germinating  immediately,  or  by  its  division  into 
2-4  daughter  cells,  giving  rise  to  a  new  colony.  Widely  dis- 
tributed plankton  algae. 

KEY  TO  THE  SPECIES  OF  DICTYOSPHAERIUM. 

i.     Cells  ovoid  or  ellipsoid.  i.     D.  Ehrenbergianum. 

i.     Cells  spherical.  2.     D. pulchellum. 

i.     Cells  reniform  or  cordate.  3.     D.  reniforme. 

1.  D.    EHRENBERGIANUM  Nageli,    1848,   p.   73,  PI.  II.  K; 
Wolle,   1887,   p.   186,   PL  CL/VI,  figs.   29-31  ;  Massee,  1891,  p. 
457,  PI.  XII.     Cells  ovoid  or  ellipsoid,  6-10X4-7  M.  membrane 
thin  ;  colonies  ovoid  or  globose,  of  16-64  cells,  up  to  80  p,  diam. 
Fig.  59.     N.  J.  Europe. 

The  first  division  of  the  cell  is  into  four ;  all  subsequent  divi- 
sions into  two,  each  division  in  a  plane  at  right  angles  to  the 
plane  of  the  previous  division  ;  reproduction  by  biciliate  zo- 
ospores,  each  formed  from  the  contents  of  a  cell,  germinating 
immediately. 

2.  D.  PULCHELLUM  Wood,  1872,  p.  84,  PL  X,  fig.  4  ;  Senn, 
1899,   p.   74,   PL   III,    figs.    1-12;  P.   B.-A.,   No.    1511.     Cells 
spherical,  5-9  yu,  diam.,  colonies  up   to  65  p.  diam.;   gelatinous 
coating  ample,  with  distinctly  radiate  structure  ;  reproduction 
not  observed.     Me.,  Mass.,  Pa.  Europe. 

3.  D.    RENIFORME  Bulnheim,    1859,   p.   22,    PL    II,    fig.   6  ; 
Wolle,    1887,  p.   186,  PL  CLVI,  fig.  28  ;   Rabenhorst,  Algen, 
No.  789.     Cells  reniform  or  subcordate,  usually  10-20X6-10 /A  ; 
colonies  to  70  /w  diam.,  somewhat  irregular  in  form  ;  gelatinous 
coating  often  with  ciliate  projections.     Me.,  Mass.,  N.  J.,  Pa. 

Europe. 

20.     DIMORPHOCOCCUS  A.  Brauu,  1855,  p.  44. 

Cells  on  gelatinous  strands  radiating  from  the  center,  at  the 
end  of  each  strand  2-8  cells  ;  all  cells  similar,  or  differing  in 
the  same  group ;  chromatophore  occupying  only  the  middle 
part  of  the  cell,  with  one  pyrenoid. 

Free  floating  plants,  resembling  Dictyosphacrinm  ;  the  develop- 
ment not  well  understood. 

D.  CORDATUS  Wolle,    1887,    p.    199,  PL   CLX,  figs.   30-38; 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  175 

P.  B.-A.,  No.  159.  Cells  all  reniform  to  cordate,  the  lobes 
turned  outward,  4-8  /*  diam.  Fig.  60.  Me.,  Mass.,  N.  Y., 
N.  J.,  Pa.,  Fla. 

The  European  D.  lunatus  A.  Br.  has  cells  in  groups  of  four ; 
two  intermediate  cells  ovoid,  obtuse ;  two  lateral  cells  lunate ; 
there  is  no  certain  record  of  its  occurrence  here,  but  it  is  to  be 
expected. 

21.     DICTYOCYSTIS  Lagerheim,  1890,  p.  5. 

Cells  in  series  on  gelatinous  branching  threads  radiating 
from  a  central  point  ;  chrotnatophore  star-shaped,  with  one  pyre- 
noid. 

D.  HITCHCOCKII  (Wolle)  L,agerheim,  1890,  p.  5  ;  Didyosphae- 
rium  Hitchcockii  Wolle,  1885,  p.  126;  1887,  p.  186,  PI.  CL,VII, 
fig.  12.  Cells  9-13X15-20  n,  ovoid,  the  longest  dimension  in 
the  line  of  radiation.  Fig.  61.  N.  J. 

Removed  from  Dictyosphaerium  on  account  of  the  stellate 
chrornatophore,  and  the  cells  arranged  along  the  gelatinous 
filaments,  not  merely  at  their  ends. 

Family  5.     HYDRODICTYACEAE. 

Cells  multinucleate,  with  net-shaped  chromatophore,  with  one 
or  more  pyrenoids  ;  united  in  families  of  definite  form  ;  asexual 
reproduction  by  biciliate  zoospores,  uniting  to  form  a  family 
either  in  the  mother  cell,  or  in  a  gelatinous  vesicle  issuing  from 
it  ;  sexual  reproduction  by  gametes  escaping  from  the  mother 
cell,  and  by  copulation  forming  a  resting  zygote,  from  which, 
by  various  intermediate  stages,  the  normal  vegetative  form  is 
produced.  Fresh  water  plants. 

KEY  TO  THE  GENERA  OF  HYDRODICTYACEAE. 

i.     Colonies  net-shape.  i.     HYDRODICTYON. 

i.     Colonies  disk-shape.  2.     PEDIASTRUM. 

i.     HYDRODICTYON  Roth,  1800,  p.  531. 

Colonies  unattached,  composed  of  very  many  cylindrical  mul- 
tinucleate cells  united  at  the  ends  by  three,  rarely  by  two  or 
four,  to  form  a  cylindrical,  wide-meshed  net  with  closed  ends  ; 
cells  all  alike  ;  asexual  reproduction  by  zoospores,  formed  in 
great  numbers  in  a  cell,  finally  arranging  themselves  in  a  mi- 
nute net,  which  is  freed  by  the  breaking  up  of  the  mother  cell ; 
sexual  reproduction  by  zoogametes  formed  in  still  larger  num- 
bers in  a  cell,  and  escaping  by  an  opening,  either  conjugating 
or  developing  parthenogenetically ;  from  the  resting  spore  thus 
formed  come  2-5  large  zoospores,  developing  into  irregular 
angular  cells,  "  polyhedra  "  in  which  are  developed  many  small 
zoospores,  uniting  to  form  a  new  net.  Only  one  species. 


176          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

H.  RETICULATUM  (I,.)  Lagerheim,  1883,  p.  71  ;  Kiitzing, 
1856,  PL  XXXV;  Wolle,  1887,  p.  169,  PI.  CUV,  figs.  11-20; 
P.  B.-A.,  No.  65.  Cells  usually  several  diameters  long,  length 
up  to  i  cm.,  100-200  /u,  wide  ;  families  i  or  2  dm.  long  ;  zoospores 
to  20,000  in  a  cell,  gametes  to  100,000.  Fig.  62.  Generally 
distributed  in  fresh  water.  Europe. 

A  very  attractive  plant  in  appearance,  the  net-like  frond  be- 
ing found  from  microscopic  size  to  one  or  two  dm.  in  length,  the 
cells  and  meshes  varying  correspondingly. 

2.     PEDIASTRUM  Meyeu,  1829,  p.  772. 

Colonies  unattached,  disk-shaped,  of  round  or  star-shaped 
outline,  continuous  or  perforate,  composed  of  marginal  cells  of 
different  shape  from  the  interior  cells  ;  cells  multinucleate,  with 
net-form  parietal  chromatophore  and  one  pyrenoid ;  asexual 
reproduction  by  biciliate  zoospores,  which  escape  from  the  cell 
enclosed  in  a  vesicular  coating,  within  which  they  arrange 
themselves  to  form  a  new  colony  ;  or  by  the  formation  of  a  new 
colony  in  a  cell,  without  intervention  of  zoospores  ;  sexual  re- 
production by  smaller  gametes,  more  in  a  cell,  copulating  to 
form  an  irregular  Polyedrium-like  zygote,  within  which  a  new 
colony  is  formed,  in  the  same  way  as  in  a  cell  of  the  mother 
colony. 

Species  of  this  genus  are  common  in  fresh  water  plankton, 
and  in  most  gatherings  of  miscellaneous  algae  from  quiet  water 
in  warm  weather.  Their  regular  disks,  continuous  or  open- 
work, with  variously  toothed  or  spiny  marginal  cells,  are  inter- 
esting objects  ;  but  while  types  of  the  species  seem  clearly  dis- 
tinct, in  practice  many  intermediate  forms  will  be  found. 

A  rather  conservative  course  has  been  followed  as  regards 
recognizing  species ;  but  it  should  be  noted  that  Chodat,  1902, 
p.  224,  includes  as  forms  of  P.  Boryanum,  the  species  P.  ford- 
patum,  P.  vagum  and  P.  angulosum  ;  this  may  sometime  be  fully 
justified,  but  for  the  present  it  will  be  more  convenient  to  retain 
them  as  species. 

KEY  TO  THE  SPECIES  OE  PEDIASTRUM. 

i.     Marginal  cells  undivided,  cuspidate.  8. 

i.     Marginal  cells  bilobed.  2. 

2.     Lobes  of  marginal  cells  simple.  3. 

2.     Lobes  of  marginal  cells  emarginate,  bidentate  or  bifid.                 7. 

3.     Disk  continuous.  4. 

3.     Disk  perforate.  ,                     7.     P.  duplex. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  177 

4.     Lobes  of  marginal  cells  incurved,  forcipate.       3.     P.  f  rcipatuin. 

4.     Lobes  of  marginal  cells  straight  or  nearly  so.  5. 

5.     Margin  finely  tuberculate-crenulate.  5.     /*.  vagum. 

5.     Margin  not  tuberculate-crenulate.  6. 

6.     Lobes  ending  in  short,  broadly  triangular  teeth. 

6.     P.  angulosum. 

6.     Lobes  ending  in  linear  teeth.  4.     P.  Boryanum. 

7.     Disk  continuous.  8.     P.  tetras. 

7.     Disk  perforate.  9.     P.  biradiatum. 

8.     Marginal  cells  with  a  single  tooth  or  cusp.  i.     P.  simplex. 

8.     Marginal  cells  tridentate.  2.     P.  tricornutum. 

1.  P.  SIMPLEX  Meyen,  1829,  p.  772,   PI.  XLJII,   figs.   1-5  ; 
Wolle,    1892,  p.    168,   PI.   LrXIV,  fig.  17;  Wittr.  and  Nordst., 
Alg.  Exsicc.,  No.  524.     Family  of  8-16,  rarely  32  cells,  up  to 
75  p.  diam.;  arrangement  much  varied,  disk  continuous  or  per- 
forate ;  each  marginal  cell  ending  in  a  single  aculeate  tooth  or 
spine. 

Var.  STURMII  (Reinsch)  Wolle,  1892,  p.  168,  PI.  L,XIV, 
fig.  1 8.  Cells  arranged  in  one  or  two  series  about  a  large  cen- 
tral open  space. 

Var.  DUODENARIUM  (Bailey)  Rabenhorst,  1868,  p.  71  ;  Wolle, 
1892,  p.  169,  PI.  LXIV,  fig.  20.  Disk  with  a  central  open 
space,  surrounded  by  four  cells,  four  openings  in  the  form  of 
arcs  of  circles  between  these  cells  and  the  12  cells  of  the  outer 
row.  Mass.,  N.  Y.,  Ohio,  111.  Europe,  So.  America. 

These  varieties  are  hardly  worthy  to  be  distinguished  by 
name,  being  merely  two  of  the  many  forms  assumed  by  this 
species.  None  of  the  forms,  however,  need  be  mistaken  for  any 
other  species,  as  there  is  no  other  species  in  which  each  cell 
ends  in  a  long,  aculeate  projection. 

2.  P.  TRICORNUTUM  Borge,  1892,  p.  4,  fig.  3.     Disk  contin- 
uous, rounded,  32-40^  diam.;  marginal  cells  10-18X9-10  ^,  tra- 
peziform,  with  three  teeth  on  the  margin  ;  disk  cells  polygonal. 
Greenland.  Northern  Europe. 

3.  P.  FORCIPATUM  (Corda)  A.  Braun,   1855,  p.  86;  Wolle, 
1892,   p.    169,   PI.   L/XIV,   figs.    21,   30-31.     Cells  8-16,  rarely 
more,   forming  a  continuous  disk  ;  disk  cells  about  24  /A  wide, 
polygonal  or  slightly  incurved  on  the  outer  side  ;  marginal  cells 
deeply   incised,    bilobed,    lobes   incurved,    acuminate.     Mass., 
N.  J.,  Pa.  Europe. 

The  small  disks,  and  especially  the  forcipate  prolongations  of 
the  marginal  cells,  seem  sufficiently  characteristic. 

4.  P.  BORYANUM  (Turp.)  Meneghini,  1840,  p.  210;  Nageli, 
1848,  p.  95,  PI.  V.B,  fig.  i  ;  Wolle,    1892,  p.   169,   PL   L,XIV, 


178  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

figs.  29-32  ;LP.  B.-A.,  No.  1180.  Cells  4-64,  rarely  128,  10-20 /u. 
wide,  foriring  a  continuous,  circular  or  elliptical  disk  ;  disk 
cells  4-6-angled,  the  external  side  varying  from  prominent  to 
repand  ;  riarginal  cells  more  or  less  emarginate  or  bilobed,  each 
lobe  ending  in  a  longer  or  shorter  terete,  obtuse  to  capitellate 
projection.  Fig.  63.  Greenland,  Me.,  Mass.,  N.  J.,  Pa.,  Ohio, 
111.,  Neb.,  Cal.,  Alaska.  Europe,  Asia,  So.  America. 

A  very  common  and  widely  distributed  species,  with  many 
varieties ;  to  be  recognized  more  by  the  general  combination  of 
characters  than  by  any  one  detail,  though  the  two  terete  pro- 
longations from  each  marginal  cell  are  usually  sufficiently 
characteristic. 

Var.  UNDULATUM  Wille,  1879,  p.  28  ;  P.  undulatum  (Wille) 
Boldt,  1893,  p.  157,  fig.  i.  Cells  sometimes  256  ;  larger  than  in 
the  type ;  disk  cells  with  irregularly  undulate  margin  ;  marginal 
cells  distinctly  bilobed.  Greenland.  Europe. 

Var.  GRANULATUM  (Kiitz.)  A.  Braun,  1855,  p.  90;  P.  B.-A., 
No.  1324;  with  smaller  cells  and  families,  and  verrucose  mem- 
brane. Greenland,  Nebraska  and  California. 

5.  P.  VAGUM  Kiitzing,  1845,  p.  143;  A.  Braun,  1855,  p.  82, 
PL  VI,  figs.  27-28  ;  P.  B.-A.,  No.  1519.     Cells  32-128  in  a  disk, 
disk  continuous,   of  varying  form,  up  to  250  ^  wide,  cells  in 
disk  to  30  p.  wide,  5-6-angular  ;   marginal  cells  about  10  /*  wide, 
with  two  short,  obtusely   triangular  projections ;    margin  and 
membrane   generally   finely   tubercular-crenulate.     Greenland, 
Me.,  Mass.  Europe,  So.  America. 

The  large  disk  of  irregular  form,  composed  of  many  cells, 
with  the  crenulate  margin,  makes  this  quite  a  distinct  species. 

6.  P.  ANGULOSUM  (Ehrenb.)  Meneghini,    1840,  p.   211;   A. 
Braun,    1855,   p.   84,   PI.  VI,  fig.  26  ;  Wolle,   1892,  p.  169,  PI. 
LXIV,  fig.  28.     Cells    16-64,   UP  to   T9  f-  diam.,  5-6-angular, 
forming  a  continuous  disk,   up  to  120  /x  diam.  ;  marginal  cells 
with  truncate  base,  wider  above,  with  a  more  or  less  deep  sinus, 
the  inner  side  of  the  ray  prolonged  in  a  slightly  incurved  tooth, 
the  outer  edge  with  a  slight  apiculum.     Me.,  N.  J.,  Ohio,  Neb., 
Alaska.  Europe,  Asia. 

Each  marginal  cell  has  a  projection  on  each  side  of  the  cen- 
tral rounded  sinus ;  the  inner  edge  of  this  terminates  in  a  sub- 
linear  tooth,  not  exactly  on  the  radial  line,  but  parallel  to  the 
tooth  on  the  other  side  of  the  sinus ;  the  outer  edge  of  the  pro- 
jection has  merely  a  small  apiculum,  as  if  produced  by  the 
pressure  of  the  adjacent  cell. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  179 

7.  P.  DUPLEX  Meyen,  1829,  p.   772,   PI.  XLJII,  figs.  6-20; 
P.  pertusum  Wolle,   1892,   PL   L,XIV,  figs.   33,  34;  Wittr.  and 
Nordst.,  Alg.  Exsicc.,  No.  1237.     Cells  8-32,  6-28  p.  wide,  form- 
ing a  disk  perforate  with  many  rounded  openings  of  varying 
size ;  disk  cells  quadrangular,  or  emarginate  on  one  or  more 
sides ;  marginal  cells  joined  only  at  the  base,  deeply  bilobed, 
lobes  straight,  each  ending  in  an.  acute  or  obtuse,  not  capitellate 
prolongation.     Mass.,  Me.,  N.  J.,  111.,  Neb.  Europe. 

A  common  species,  and  with  many  varieties ;  but  fairly  well 
recognized  by  the  numerous  rounded  openings. 

Var.  CLATHRATUM  A.  Braun,  1855,  p.  93  ;  Wittr.  and  Nordst., 
Alg.  Exsicc.,  No.  1562.  Disk  cells  deeply  emarginate,  making 
the  openings  proportionally  larger  than  in  the  type.  Mass., 
Neb.  Europe. 

Var.  BRACHYLOBUM  A.  Braun,  1855,  p.  93,  PI.  VI,  fig.  25; 
Wolle,  1892,  PI.  L-XIV,  fig.  35.  Disk  and  marginal  cells  only 
slightly  emarginate  ;  openings  and  marginal  projections  incon- 
spicuous. Me.  Europe. 

8.  P.  TETRAS  (Ehrenb.)  Ralfs,  1844,  p.  469,  PL  XII,  fig.  4; 
P.  Ehrenbergii  A.  Braun,  1855,  p.  97,  PL  V.H.  ;   Wolle,    1892, 
p.   170,   PL  LXIV,  figs.  25-27.     Cells  4-16,  9-20  /x  wide,  disk 
cells  polygonal,  one  side  repand  or  with  a  very  deep  and  narrow 
incision  ;  marginal  cells  very  deeply  incised,  lobes  emarginate, 
bidentate  or  bifid.     Me.,  Mass.,  N.  J.,  Ohio,  111.,  Neb.,  Colo., 
Porto  Rico,  Mexico.  Europe,  Asia,  So.  America. 

The  small  continuous  disk,  with  deep  linear  incisions  in 
nearly  every  cell,  and  with  cell  lobes  divided,  easily  identifies 
this  species. 

9.  P.  BIRADIATUM  Meyen,    1829,  p.   773,   PL    XLJII,   figs. 
21-22;    P.    rotula    A.  Braun,    1855,   p.    101,   PL   VI,    figs.    1-3. 
Cells  8-32,  9-21  p  wide  ;  disk  cells  deeply  incised,  leaving  rather 
large  openings  ;  marginal  cells  attached  at  the  base  only,  in- 
cised to  or  below  the  middle,  each  division  ending  in  two  acute 
or  obtuse  denticulations.     Greenland.  Europe. 

From  P.  duplex,  which  has  a  similarly  perforate  frond,  this 
can  be  distinguished  by  the  double  division  of  the  marginal 
cells,  giving  two  projections  to  each  lobe. 

Var.  EMARGINATUM  (A.  Braun)  L,agerheim,  1882,  p.  54; 
P.  rotula  var.  emarginatum  A.  Braun,  1855,  p-  102,  PL  VI,  figs. 
4,  8,  9,  ii.  Disk  cells  slightly  sinuate-emarginate ;  marginal 
cells  less  deeply  incised,  divisions  emarginate,  bidentate  or  sub- 
truncate.  Greenland.  Europe. 


i8o  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Order  ULOTRICHALES 

Simple  or  branched  filaments,  sometimes  membranes,  rarely 
in  few-celled  families ;  cells  uninucleate,  chromatophore  usually 
single,  band-,  disk-,  net-,  or  star-shape,  generally  with  one 
or  more  pyrenoids.  Marine  and  fresh  water. 

KEY  TO  THE  FAMILIES  OF  ULOTRICHALES. 
i.     Chromatophore  star-shaped  ;  zoospores  unknown. 

3.    PRASIOLACEAE. 

i.     Chromatophore  net-,  disk- or  band-shaped.  2. 

2.     Cells  usually  red  or  brown  by  haematochrome  ;  frond  filamentous, 

branching.  9.     CHROOLEPIDACEAE. 

2.     Vegetative  cells  true  green.  3. 

3.     Fronds  unbranched  filaments.  4. 

3.     Fronds  branched  or  membranaceous,  rarely  in  few-celled  families. 

6. 

4.     Sexual  reproduction  by  isogamous  gametes,     i.     ULOTRICHALES. 

4.     Sexual  reproduction  by  oogonia  and  antheridia.  5. 

5.     Chromatophore  net-shaped.  5.     OEDOGONIACEAE. 

5.     Chromatophore  disk-  or  band-shaped.        4.     CYLINDROCAPSACEAE. 

6.     Frond  membranaceous,  either  flat  or  forming  a  tube. 

2.    ULVACEAE. 
6.     Frond    filamentous,   branching,  or  a   few-celled   family ;    usually 

with  hairs.  7. 

7.     Sexual  reproduction  by  isogamous  zoogametes. 

6.    CHAETOPHORACEAE. 

7.     Sexual  reproduction  by  oogonia  and  antheridia.  8. 

8.     Vegetative  filaments  prostrate.  9. 

8.    Vegetative  filaments  erect.  5.     OEDOGONIACEAE. 

9.     Oospore   with    cellular    envelope;    vegetative  filaments   radiate  or 

united  to  a  disk.  8.    COLEOCHAETACEAE. 

9.     Oospore  without  cellular  envelope;  vegetative  filaments  irregularly 
spreading.  7.    HERPOSTEIRACEAE. 

Family  i.     ULOTRICHACEAE. 

Frond  a  normally  unbranched,  uniseriate  filament,  rarely 
partly  multiseriate,  of  uninucleate  cells,  each  of  which,  with  the 
exception  of  the  basal  cell,  when  present,  is  capable  of  produc- 
ing spores  or  gametes.  Chromatophore  either  a  single,  complete 
or  broken  band,  or  a  network,  or  one  to  several  disks ;  usually 
with  one  or  more  pyrenoids.  Asexual  reproduction  by  bi-  or  4- 
ciliate  zoospores,  by  akinetes,  or  by  aplanospores ;  sexual  repro- 
duction by  the  conjugation  of  biciliate  zoogametes. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  181 

A  family  of  fresh  water  and  marine  algae,  fairly  well  marked 
off  from  other  forms  by  the  characters  just  given  ;  but  it  is  by 
no  means  easy  to  determine  by  hasty  inspection  whether  a  plant 
belongs  to  this  family  or  to  the  Cladophoraccae .  In  external  ap- 
pearance and  even  by  ordinary  microscopic  inspection,  there 
is  no  test  to  distinguish  Ulothrix,  Hormisda,  or  Chaetomorpha  ; 
only  by  actual  acquaintance  with  the  individual  species  can  one 
acquire  any  certainty  of  determination. 

In  the  arrangement  of  this  family  Hazen,  1902,  has  been  fol- 
lowed, except  that  Conferva  has  been  removed.  While  there 
may  be  some  doubt  as  to  the  distinctness  of  all  the  species  he 
has  accepted,  and  he  himself  expresses  some  such  doubt,  his 
work  represents  the  only  careful  and  continued  study  that  has 
been  made  of  the  living  plants  in  this  country,  and  may  well  be 
accepted  until  modified  by  later  investigations. 

KEY  TO  THE  GENERA  OF  ULOTRICHACEAE. 
i.     Filaments  tnonosiphonous  below,  parenchymatous  above. 

4.     SCHIZOMERIS. 

i.     Filaments  monosiphonous  throughout.  2. 

2.     Cells  loosely  attached,  in  a  wide,  gelatinous  sheath. 

3.    RADIOFI^UM. 

2.     Cells  forming  a  cylindrical  or  moniliform  filament,  without  ex- 
ternal gelatinous  sheath.  3. 
3.     Without  pyrenoid.                                                          6.     MICROSPORA. 
3.     With  one  or  more  pyrenoids.                                                                   4. 
4.     Chromatophore  a  parietal  disk  or  plate.             5.     STICHOCOCCUS. 
4.     Chromatophore  a  zonate  band,  sometimes  incomplete.  5. 
5.     Apical  and  basal  cells  attenuate.                                     2.     URONEMA. 
5.     Apical  and  basal  cells  little  if  at  all  differentiated,     i.     UI.OTHRIX. 

i.     ULOTHRIX  Kiitzing,  1833,  p.  517. 

Filaments  of  a  single  series  of  uninucleate  cells,  all  similar, 
and,  with  the  exception  of  the  attached  basal  cell,  capable  of 
division  and  of  producing  spores.  Chromatophore  band-shaped, 
with  one  or  more  pyrenoids.  Asexual  reproduction  by  aplano- 
spores  and  akinetes,  also  by  4-ciliate  zoospores,  with  red  stigma, 
formed  1-4  in  a  cell,  germinating  immediately;  sexual  repro- 
duction by  biciliate  zoogametes  formed  8  or  more  in  a  cell, 
germinating  after  conjugation.  External  conditions  may  induce 
many  modifications  of  the  normal  process  ;  resting  spores  may  be 
formed,  ultimately  producing  zoospores;  filaments  may  break 
up  into  individual  cells,  and  these  by  copious  formation  of 
gelatine  pass  into  a  Palmella  or  a  Gloeocystis  condition. 


182          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

A  genus  of  marine  and  fresh  water  species,  of  world-wide  dis- 
tribution ;  by  no  means  easy  to  distinguish  from  species  of  Hor. 
miscia,  Chaetomorpha,  etc.,  whose  filaments  are  also  of  a  single 
series  of  cylindrical  or  somewhat  inflated  cells.  The  number  of 
nuclei  can  be  ascertained  only  by  careful  examination,  and 
while  the  shape  of  the  chromatophore  is  of  a  different  type  in 
each  genus,  the  variations  from  the  type  are  many  and  perplex- 
ing. In  herbarium  specimens  the  chromatophore  characters 
are  usually  indistinct.  In  general,  Chaetomorpha  is  firmer  and 
stiffer,  and  has  longer  cells  than  Ulothrix  ;  none  of  our  species 
of  Ulothrix  exceeds  50  /A  diam.,  while  few  species  of  Chaetomor- 
pha are  less  than  100  /u.  diam.  Hormiscia  species  also  are 
usually  of  larger  dimensions  than  Ulothrix  species,  but  there  is 
little  difference  in  cell  length  or  consistency.  As  between  the 
two  genera,  the  only  tests  are  the  number  of  nuclei,  requiring 
pretty  careful  study,  and  the  form  of  the  zoospores,  ascertain- 
able  only  occasionally.  As  regards  dried  specimens,  only  per- 
sonal acquaintance  with  the  various  species,  or  comparison  with 
authentic  specimens,  is  of  any  use. 

KEY  TO  THE  SPECIES  OF  ULOTHRIX. 

i.     Marine  or  brackish.  2. 

i.     Fresh  water.  5. 

i.     Thermal.  2.     U.  caldaria. 

2.     Occasionally  branching.  12.     U.  laetevirens. 

2.     Always  simple.  3. 

3.     Cells  usually  much  shorter  than  their  diameter.          10.     U.flacca. 
3.     Cells  usually  longer  than  their  diameter.  4. 

4.     Chromatophore  a  more  or  less  complete  ring  at  the  middle  of  the 
cell.  9.     U.  implexa. 

4.     Chromatophore  a  curved  lateral  disk,  extending  from  the  pyrenoid 

in  all  directions,  but  not  filling  the  cell.       n;     U.  subflaccida. 
5.     Filaments  not  over  9  /u.  diam.;  pyrenoid  single.  6. 

5.     Filaments  11-45  f-  diam.;  pyrenoids  several.  7. 

6.     Filaments  7-9  n  diam.  3.     £/.  tenerrima. 

6.     Filaments  5-6 /x  diam.  i.     U.  variabilis. 

7.     Mature  filaments  25-45  /x  diam.  8.     U.  zonata. 

7.     Filaments  not  over  20  IJL  diam.  8. 

8.     Filaments  torulose.  6.     (7.  moniliformis. 

8.     Filaments  not  torulose.  9. 

9.     Cells  1-2  diam.  long.  7.     U.  aequalis. 

9.     Cells  not  over  i  diam.  long.  10- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  183 

10.     Cells  15-20  /j.  diam.  4.     U.  tenuissima. 

10.     Cell  ii  M  diam.  5.     U.  osdllarina. 

1.  U.  VARIABILIS  Kiitzing,   1849,  p.  346;  Hazen,   1902,  p. 
152,  PI.  XXI,  figs.  5-7  ;  P.B.-A.,  Nos.  1022,  1373;  ?  U.  snbtilis 
var.  variabilis  Wolle,    1887,  p.    136,   PI.   CXVIII,   figs.    15-16. 
Filaments  5-6  //.  diam.,  cells  cylindrical,  ^-i^  diam.  long,  wall 
very  thin  and  delicate  ;  chromatophore  usually  occupying  about 
half  the  cell  wall,  often  quite  irregular  in  shape  and  position  ; 
pyrenoid  single,  small.  Europe. 

This  species  forms  floccose  masses  in  brooks  and  quiet  waters. 
It  has  been  reported  from  Greenland,  a  few  localities  in  the 
eastern  States,  from  Trinidad,  and  from  California. 

2.  U.  caldaria   (Kiitz.)  nov.  comb.  ;   Gloeotila  caldaria  Kiitz- 
ing,  1849,  p.  363;   1853,  p.    10,  PI.  XXXII,  fig.  3;    U.  snbtilis 
var.  thermarum  Wolle,    1887,  p.   136,  PI.  CXVIII,  figs.  18  and 
19  ;  Hormisda  flaccida  var.  caldaria  Tilden,   Amer.  Algae,  No. 
130.     Filaments  soft  and  mucilaginous,  bright  or  dull  green, 
5-8  fj.  diam.,  cells   1-3  diam.  long,  cylindrical ;  chromatophore 
(in  dried  specimens)  apparently  occupying  the  entire  cell  wall. 
Forming  long  strings  and  floccose  masses  in  warm  or  hot  water. 
Yellowstone  Park  ;  Pa.  Europe. 

Our  only  distinctly  thermal  species. 

3.  U.  TENERRIMA   Kiitzing,    1843,   p.    253,    PI.   IX,  fig.   i  ; 
Hazen,     1902,    p.    151,    PI.    XXI,  figs.   3  and    4;  P.   B.-A., 
No.    1468.      U.  snbtilis  var.  tenerrima  Wolle,    1887,  p.  136,  PI. 
CXVIII,  fig.   17.     Forming  light  green  silky  masses,  often  of 
considerable   length;    filaments  7-9  /M  diam.;  cells  cylindrical, 
y$-\yi  diam.  long;  wall  very  thin;  chromatophore  zonate,  or 
contracted  to  one  side  of  the  cell ;  pyrenoid  single.     Vt.,  Mass., 
Cal.  Europe. 

The  single  pyrenoid  seems  to  distinguish  this  species  from  all 
others  except  U.  variabilis ;  these  two  species  are  certainly 
quite  near  each  other,  but  U.  tenerrima  is  a  larger  species,  with 
the  chromatophore  more  fully  and  regularly  developed.  The 
material" from  California  distributed'as  P.  B.-A.,  No.  1468,  is  in 
the  Gloeocystis  state,  and  its  connection  with  this  species 
though  probable  is  not  certain. 

4.  U.  TENUISSIMA  Kiitzing,  18333,  p.  518;  Hazen,  1902,  p. 
149,    PI.    XX,   figs.    5  and  6;  P.  B.-A.,  No.  1021.     Filaments 
dark  green,  15-20  p.,  rarely  25  /*  diam.;  cells  cylindrical,  except 
when  fruiting,   about   }4   diam.  long;    chromatophore  a  broad 
band. 


184    TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

This  species  resembles  young  conditions  of  U.  zonata,  and 
even  Hazen,  on  whose  authority  it  is  given,  is  in  doubt  if  it 
may  not  have  to  be  included  in  the  commoner  species  when  bet- 
ter known.  The  distinctions  are  in  the  darker  color,  thinner 
cell  wall  and  shorter  cells,  characters  which  are  notoriously  va- 
riable in  this  genus.  The  only  localities  are  near  New  York 
city  and  in  Alaska.  Europe. 

5.  U.  osciLivARiNA  Kiitzing,  1845,  p.  197;  ?Wolle,  1887,  p. 
137,  PI.  CXVIII,  figs.  34-36;  Hazen,    1902,  p.  150;  P.  B.-A., 
No.  613.     Forming  soft  mucilaginous  masses  ;  filaments  about 
ii   /x.  diatn.;  cells   %-%  diam.  long,  rarely  i  diam.;  chromato- 
phore  a  broad  band.     Mass.  Europe. 

In  quiet  or  slowly  running  water.  The  short  cells  and  soft, 
mucilaginous  consistency  are  the  chief  distinguishing  characters. 
Wolle  reports  it  from  Wisconsin,  but  if  his  figure  is  drawn  from 
Wisconsin  specimens,  there  might  be  some  question  as  to  the 
identity  of  his  plant  with  the  present  species.  Hazen  reports 
the  specimens  in  the  Wolle  herbarium  not  to  be  Ulojhrix. 
U.  oscillarina  appears  to  be  a  plant  of  summer  rather  than  of 
spring. 

6.  U.    MONIUFORMIS    Kiitzing,    1849,    p.    347 ;     1852,    PI. 
LXXXVIII,  fig.  4;  Hazen,   1902,  p.  157;  P.  B.-A.,  No.  612. 
Filaments  11-14  /*  diam.,  more  or  less  crisped,  torulose,  light 
green,  with  thick  walls  ;  cells  about  as  long  as  broad.      Europe. 

This  may  be  the  fruiting  condition  of  some  other  species,  but 
it  has  not  yet  been  identified  with  any,  and  it  is  quite  distinct  in 
form  from  any  of  the  species  here  recorded.  It  has  only  one 
authentic  locality  with  us,  in  Conn. 

7.  U.  AEQUAUS  Kiitzing,  1845,  p.  197  ;  Wolle,  1887,  p.  134, 
PL    CXVIII,    figs.  3-5 ;    Hazen,    1902,   p.    150 ;    Phyk.    Univ., 
No.  577.     Filaments  13-16  /u,  diam.,  cylindrical,  cells  1-2  diam. 
long.  Europe. 

A  rather  imperfectly  known  species,  but  considered  quite  dis- 
tinct by  Hazen.  The  only  definite  locality  is  near  New  York 
City. 

8.  U.   ZONATA  (Web.  and    Mohr)    Kiitzing,  18333,  p.   519- 
Wolle,   1887,   PI.   CXVII,   figs.    1-19.;  Hazen,  1902,  p.  147,  Pi! 
XX,  figs.  1-4;  P.  B.-A.,  Nos.  iga  and  1023.     Forming  yellow- 
ish  green  masses;  filaments  usually  30-40 /*  diam.,   sometimes 
as  low  as  1 1  /A  at  the  base  of  young  filaments,  rarely  45  /x  in  old 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  185 

filaments;  cells  cylindrical  or  somewhat  swollen,  y$-il/>  diam. 
long  when  full  grown,  longer  in  young  filaments  ;  cell  wall  at 
first  thin,  growing  thicker ;  chromatophore  a  broad  or  narrow 
band  at  the  middle  of  the  cell,  with  several  large  pyrenoids. 
Fig.  64.  Greenland,  Northern  U.  S.  from  Me.  to  Alaska. 

I  Europe. 

A  common  species  in  spring,  attached  to  sticks  or  stones  in 
streams  or  pools  ;  the  filaments  are  nearly  the  same  diameter 
throughout,  or  smallest  at  the  base,  considerably  larger  above  ; 
the  cells  are  usually  actually  as  well  as  relatively  longer  near 
the  base.  It  is  not  likely  to  be  mistaken  for  other  fresh  water 
species  of  Ulothrix,  but  it  is  not  unlike  Microspora  -crassior  and 
M.  amocna,  which  occur  in  similar  stations.  The  characters  of 
the  chromatophores  and  of  the  cell  wall  can  be  depended  on  for 
distinction  in  the  living  plant. 

9.  U.    IMPLEXA  Kiitzing,   1849,    p.  349;    1852,   PI.  XCIV, 
fig.  2  ;   Hazen,  1902,  p.  153,  PI.  XXI,  figs,  i   and  2  ;   P.  B.-A., 
No.   115.     Forming  light  green,  soft  masses,  cells  6-15  //,  diam., 
sometimes  slightly  swollen   at  the   middle,   about  as   long  as 
broad,  chromatophore  occupying  only  the  middle   part  of   the 
cell,  often  an  incomplete  ring.     Atlantic  coast  and  Alaska. 

Europe. 

Rather  common  from  New  Jersey  to  Greenland,  usually  near 
high  water  mark,  and  where  it  is  more  or  less  exposed  to  the  in- 
fluence of  fresh  water ;  most  frequent  in  spring.  Reported  from 
Florida  by  Wolle,  but  the  identification  is  doubtful. 

10.  U.  FLACCA   (Dillw.)   Thuret  in  Le  Jolis,   1863,  p.  56; 
Farlow,  1881,  p.  45;  Hazen,   1902,  p.  155,  PI.  XX,  figs.  7-9; 
P.  B.-A.,  Nos.  17,  1123;  Hormotrichum  spetiosum  and  ff.  bore- 
ale  Harvey,  1858,  p.  90.     Forming  bright  or  dark  green,  often 
much  entangled  masses  or  skeins  ;  cells  10-25  P-  diam.,  J4~H  a& 
long  as  broad ;  when  producing  spores  up  to  50  /x  broad,  and 
swollen  in  the  middle ;  chromatophore  occupying  the  whole  of 
the  cell  wall.     Atlantic  and  Pacific  coasts.  Europe. 

Common  between  tide  marks  from  New  Jersey  to  Greenland, 
and  occurring  on  the  Pacific  coast  from  Washington  to  Califor- 
nia ;  in  southern  New  England  chiefly  on  Fucus  and  Spartina 
(Hazen,  1902,  p.  156)  ;  more  northerly,  abundant  on  rocks  and 
woodwork,  often  forming,  in  company  with  Hormisda  penicilli- 
formis  and  Bangia  fusco-purpurea ,  a  band  along  the  shore  be- 


1 86  TUFTS  COLLEGE  STUDIES,  Voi,.  II,  No.  3 

tween  half  tide  and  low  water  mark,  for  a  long  distance.  It  is 
most  abundant  in  winter  and  spring,  but  is  found  more  or  less 
throughout  the  year. 

Several  species  have  been  segregated  by  Wille,  1901,  from 
U.  flacca ;  the  new  species  are  not  at  all  easy  to  distinguish, 
except  when  living ;  probably  all  have  passed  as  forms  of 
U.  flacca  in  this  country.  The  most  certain  marks  of  this 
species  are  the  always  free  filaments,  with  short  cells,  quite 
occupied  by  the  chromatophore,  which  is  of  nearly  even  thick- 
ness throughout. 

11.  U.  SUBFLACCIDA  Wille,    1901,  p.   27,   PI.  Ill,   figs.  90- 
100  ;  P.  B.-A.,  No.  1275.     Filaments  5-25  p.  diam.,  attached  by 
a  rounded  basal  cell ;  cells  1-2  diarn.  long,  rarely  more  or  less  ; 
chromatophore   a    curved    parietal    disk,    with   one   pyrenoid ; 
zoospores  formed  8  in  a  cell,  broadly  ovoid. 

Segregated  from  U.  flacca  by  Wille,  this  species  is  to  be  rec- 
ognized chiefly  by  the  longer  cells,  with  the  chromatophore 
quite  thick  at  one  side,  where  the  pyrenoid  is  situated,  thinner 
in  all  directions,  often  not  extending  around  the  cell  or  to  the 
ends.  The  only  locality  with  us  is  at  California,  where  it  was 
found  growing  on  a  steamer  whose  daily  route  passed  from  fully 
salt  to  fully  fresh  water.  Such  exceptional  conditions  would 
naturally  have  their  results  on  the  plant,  and  it  is  of  course 
possible  that  under  more  normal  conditions  it  would  be  different. 
At  present  it  answers  well  to  Wille's  species. 

12.  U.  laetevirens  (Kiitz.)  nov.  comb.  ;  Schizogonium  laete- 
virens  Kiitzing,  1845,  p.  194;   P.  B.-A.,   No.  313.     (?)  U.conso- 
ciata  Wille,  1901,  p.  25,  PI.  II,  figs.  82-89.     Filaments   10-25  f- 
diam.,  two  or  three  often  firmly  grown  together  laterally,  more 
or  less  entangled  and  creeping  ;   with  not  infrequent  branches, 
issuing  at  a  wide  angle,  and  usually  much  more  slender  than 
the  main  filament,  of  many  cells,  which  are  generally  1-3  diam. 
long  ;  filaments  tapering  towards  the  base,  the  lower  cells  of  the 
densely  packed   filaments   often  subparenchymatously  united ; 
cells   %-Y\  diam.   long,  rarely  more;  chromatophore  covering 
nearly  or  quite  all  of  the  cell  wall,  but  thicker  at  one  side, 
where  the  pyrenoid  is  situated  ;  zoospores  usually  8  in  a  cell ; 
akinetes  formed  singly  from  the  cells.     On  woodwork  between 
tides.     Canada,  Me.,  Cal.  Europe. 

The  Canadian  plant  grew  on  alder  logs  at  Cap  a  PAigle  ;  the 
material  distributed  as  P.  B.-A.,  No.  313,  on  fence  rails  be- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  187 

tween  tide  marks,  at  Eagle  Island,  Penobscot  Bay,  Maine. 
This  material  agrees  very  well  with  authentic  specimens  of 
Schizogonium  lactevircns  from  Calvados,  the  locality  given  by 
Kiitzing  ;  whether  Bangia  laetcvirens  Harvey  in  Hooker,  1833, 
p.  317,  is  the  same,  can  hardly  be  determined  ;  that  species  is 
ignored  by  Harvey  in  his  later  works. 

The  description  of  U.  consociata  Wille  would  seem  to  indicate 
the  same  species.  It  is  our  only  species  of  this  genus  with 
branching  filaments ;  the  laterally  united  filaments  are  also 
characteristic,  resembling  those  of  Schizogonium  ;  they  arise, 
however,  by  the  union  of  distinct  filaments,  not  by  longitudinal 
division  of  a  single  filament. 

The  genus  Hormospora  Brebisson,  has  cells  practically  like 
those  of  Ulothrix,  but  located  at  a  greater  or  less  distance  from 
each  other  in  a  relatively  large  gelatinous  filament.  Several 
species  have  been  described,  but  Cienkowski,  1876,  has  shown 
that  under  certain  conditions  a  species  of  Ulothrix  passed  into  a 
state  agreeing  perfectly  with  the  description  of  Hormospora, 
and  then  by  further  development  into  a  Palmetto,  state.  Gay, 
1891,  states  that  he  has  examined  a  number  of  authentic  speci- 
mens of  the  original  species,  H.  mutabilis  Breb.,  and  found  all 
stages  from  normal  Ulothrix  to  typical  Hormospora.  At  least 
four  species  in  this  genus  were  proposed  by  Wolle  at  different 
times,  but  in  Wolle,  1887,  pp.  133,  189,  he  appears  to  have 
given  up  his  belief  in  them.  In  PI.  CXXIV  of  the  same  work 
are  figured  a  number  of  forms,  one  of  which,  H.  purpurea  Wolle, 
1880,  p.  22,  seems  to  be  a  good  species,  but  until  more  is  known 
of  its  life  history,  its  affinities  must  be  doubtful,  but  with  a  prob- 
ability that  it  belongs  with  the  Rhodophyceae ,  among  the  Bangi- 
aceae.  It  has  been  distributed  from  Pa.  in  Wittr.,  Nordst.  and 
Lagerh.,  Alg.  Exsicc.,  No.  1358,  and  from  N.  H.  in  P.  B.-A., 
No.  1374.  Fig.  65. 

The  only  other  species  for  which  there  is  a  record  in  this 
region  has  recently  been  described  by  G.  S.  West,  who 
thinks  that  the  genus  should  be  maintained,  at  least  provision- 
ally. As  this  species  is  quite  different  from  species  previously 
described,  and,  if  a  condition  of  Ulothrix,  probably  related  to 


i88  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

some  undescribed  species,  it  appears  well  to  give  the  descrip- 
tion here. 

H.  SCALARIFORMIS  G.  S.  West,  1905,  p.  282,  PI.  CCCCL,XIV, 
figs.  6  and  7.  Cells  narrowly  oblong-ellipsoid,  rather  distant, 
7-8.5  by  about  2.5  p.,  set  transversely  in  the  cylindrical,  gelati- 
nous filaments,  13-17  p-  diam.  Barbados. 

2.  URONEMA  L,agerheim,  1887,  p.  517. 
Filaments  attached,  simple,  of  a  single  series  of  cells,  apical 

and  basal  cells  attenuate  ;  chromatophore  a  parietal  disk,  with 
two  pyrenoids,  rarely  only  one  pyrenoid  ;  asexual  reproduction 
by  4-ciliate  zoospores  produced  singly,  sometimes  two,  in  any 
cell  of  the  filament,  escaping  by  an  opening,  germinating  at 
once  ;  also  by  aplanospores,  formed  one  in  a  cell.  Only  one 
species. 

U.  CONFERVICOLA  Lagerheim,  1887,  p.  518,  PI.  XII,  figs, 
i-io;  Wittr.  and  Nordst.,  Alg.  Exsicc.,  No.  910.  Filaments 
up  to  i  mm.  long,  solitary,  cylindrical,  apical  cell  acuminate, 
basal  cell  attenuate,  terminating  in  a  callus;  cells  4-6  p.  diam., 
2^-4  diam.  long,  basal  and  terminal  cells  considerably  longer; 
usually  attached  to  other  algae.  Fig.  66.  W.  I.,  Cal.  Europe. 

Gaidukow,  1903,  claims  that  under  certain  conditions  a  plant 
that  he  designates  as  Ulothrix  flaccida  var.  genuina  Hansgirg, 
developed  filaments  with  pointed  ends ;  and  that  therefore  Uro- 
nema  should  be,  at  most,  merely  a  subgenus  of  Ulothrix.  There 
might  be  some  question  as  to  what  species  Gaidukow  had  under 
investigation  ;  Hansgirg  gave  a  very  broad  extension  to  Ulo- 
thrix flaccida,  and  his  views  on  polymorphy  of  algae  are  well 
known  ;  as  here  understood,  Ulothrix  flaccida  Kiitz.  belongs  in 
the  genus  Stichococcus ,  having  only  one  pyrenoid  to  a  cell,  bicil- 
iate  asexual  zoospores,  and  no  differentiated  basal  cell.  This 
certainly  does  not  agree  with  Uronema,  and  as  U.  confervicola  has 
been  found  in  very  distant  stations,  practically  the  same,  it 
seems  best  to  retain  it,  pending  further  developments. 

3.  RADIOFILUM  Schmidle,  1894,  p.  47. 

Cells  usually  not  as  long  as  broad,  subglobose,  ellipsoid  or 
lenticular,  with  parietal  chromatophore  and  one  pyrenoid,  ar- 
ranged in  longitudinal  series,  in  a  wide,  gelatinous,  cylindrical 
sheath. 

R.  APICULATUM  W.  and  G.  S.  West,   1895^  p.  52  ;  Bohlin, 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  189 

1897,  p.  10,  PI.  I,  figs.  6-8;  P.  B.-A.,  No.  1421.  Cells  lenticu- 
lar with  sharp  edge,  about  6  p.  diam.,  4  p.  thick,  set  transversely 
in  a  transparent  gelatinous  sheath,  20-25  P-  diam.  Fig.  74. 
Mass.  So.  .-Inicrica. 

The  filaments  of  this  species  are  found  among  various  unat- 
tached algae  in  quiet  water.  The  cell  wall  appears  to  consist 
of  two  equal  parts,  something  like  two  soup  plates  set  face  to 
face  ;  in  the  filament  these  show  the  edge  view,  the  outline 
being  an  oval  with  acuminate  ends. 

4.     SCHIZOMERIS  Kiitzing,  1843,  p.  247. 

Frond  filiform,  unbranched,  of  a  single  series  of  cells  below, 
increasing  in  size  above,  cells  dividing  in  all  directions  ;  repro- 
duction by  biciliate  zoospores  with  red  stigma  ;  asexual  (?). 
Fresh  water. 

Only  one  species. 

S.  LEIBLEINII  Kiitzing,  1843,  p.  247,  PI.  XII,  fig.  i  ;  Wolle, 
1887,  PI.  CXXV.  ;  P.  B.-A.,  No.  69.  Frond  up  to  20  cm. 
high,  rather  stiff,  20-25  P-  diam.  at  base,  up  to  150  p.  above  ; 
terete  below,  with  more  or  less  deep  and  frequent  constrictions 
above;  cells  15-30  p.  diam.,  roundish  or  angular,  with  rather 
thick,  often  lamellate  membrane  ;  zoospores  formed  in  the  upper 
part  of  the  frond,  freed  by  the  breaking  of  the  cross  walls,  the 
side  walls  dissolving  later ;  zoospores  thus  issuing  from  the 
summit  of  the  frond.  Fig.  67.  In  quiet  fresh  water.  Mass., 
R.  I.,  N.  J.,  Pa.,  Fla.  Europe,  So.  America. 

5.     STICHOCOCCUS  Nageli,  1848,  p.  76. 

Filaments  without  special  basal  cell,  slender,  consisting  of 
few  or  many  cells ;  chromatophore  a  parietal  disk  or  plate,  not 
covering  more  than  half  the  cell  wall,  containing  one  pyrenoid. 
Vegetative  reproduction  by  the  breaking  up  of  the  filament  into 
individual  cells,  which  may  be  considered  as  akinetes ;  asexual 
reproduction  by  biciliate  zoospores  without  stigma,  formed 
singly  in  a  cell,  escaping  by  a  small  hole  in  the  wall,  and  ger- 
minating without  forming  a  holdfast. 

Species  of  Stichoccocus  occur  in  fresh  water,  rarely  in  salt  or 
brackish  water,  and  also  in  moist  places  not  under  water.  The 
smaller  species  of  Ulothrix,  with  chromatophore  of  irregular 
shape,  are  not  easily  distinguished  from  species  of  Stichococcus  ; 
but  the  biciliate  spore  of  the  latter,  the  absence  of  a  basal  cell, 
and  the  tendency  of  the  filaments  to  break  up  into  individual 
cells,  seem  to  justify  keeping  it  as  a  separate  genus. 


igo          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

KEY  TO  THE  SPECIES  OF  STICHOCOCCUS. 

I.     Cells  cylindrical.  2. 

i.     Cells  swollen.  4. 

2.     Plant  of  moist  places,  not  submerged.  i.     5".  bacillaris. 

2.     Aquatic.  3. 

3.     Marine.  3.     6".  marinus. 

3.     Fresh  water.  6. 

4.     Cells  usually  over  5  M  diam.  4.     51.  subtilis. 

4.     Cells  usually  under  5  M  diam.  5. 

5.     Cells  3-3.5  fj-  diam.,  i-io  diam.  long.  2.     S.  scopulinus. 

5.     Cells  2.5-3  A*  diam.,  1-4  diam.  long. 

i.     S.  bacillaris f.  confervoideus. 

6.     Plant  of  moist  places,  not  submerged.  5.     S.flaccidus. 

6.     Fresh  water  plants,  submerged.  7. 

7.     Unbrauched  ;  filaments  readily  breaking  up.  6.     S.fluitans. 

7.     With  rhizoidal  branches  ;  not  readily  breaking  up.  7.     S.  rivularis. 

1.  S.  BACILLARIS  Nageli,   1848,  p.  77,   PL   IV. G.,   fig.   i; 
Hazen,    1902,    p.    160,   PI.   XXII,    fig.    i  ;   P.  B.-A.,   No.  1024. 
Filaments  pale  green,  2.5-3  /"•  diam.,  cylindrical,  of  2-24  cells, 
very  readily  separating;  cells  1-4  diam.  long;  chromatophore 
elliptical,  thin  and  pale.     Fig.  69.     On  damp  ground,  rocks,  and 
on  flower-pots  in    greenhouses.     Nova    Scotia,   N.  H.,   Mass., 
N.  Y.,  Kansas,  N.  C.,  Cal.  Europe. 

Forma  CONFERVOIDEUS  Hazen,  1902,  p.  160,  PI.  XXII,  figs. 
2  and  3.  Submerged  form ;  filaments  longer,  not  so  readily 
breaking  up.  Found  among  other  algae,  in  rather  quiet  water, 
forming  crisped  or  floccose  masses.  Mass,  to  N.  J. 

2.  S.  SCOPULINUS  Hazen,  1902,  p.  161,  PI.  XXII,  figs.  4-6. 
Filaments  forming  long,  bright  green,  lubricous  masses;  cells 
cylindrical,   3-3.5  M  diam.,    i-io   diam.    long;  wall   very   thin, 
chromatophore  pale,  slender  ;  pyrenoid  indistinct. 

Slightly  larger  than  S.  bacillaris  forma  confervoidea ,  and  with 
longer  cells  ;  at  the  original  locality,  near  New  York  city,  the 
only  station  yet  recorded,  it  formed  long  skeins  on  dripping 
rocks  ;  when  collected  it  soon  breaks  up,  or  produces  abundant 
zoospores. 

3.  S.  MARINUS  (Wille)  Hazen,  1902,  p.  161,  PI.  XXI,  figs. 
8  and  9;    Ulothrix  variabilis  var.  marina  Wille,   P.  B.-A.,   No. 
615.     Filaments  dark  green  ;  cells  cylindrical,  5-6  /A  diam.,  cells 
1-2  diam.  long;    chromatophore   a   roundish  or  oblong  plate; 
pyrenoid  indistinct.     Me.,  R.  I.,  Conn.,  Cal.    Northern  Europe. 

The  only  marine  species ;  much  more  slender  than  any  of  our 


THE  GREEN  ALGAE  OK  NORTH  AMERICA  191 

marine  species  of  Ulothrix,  which  are  the  only  plants  for  which 
it  could  be  mistaken. 

4.  S.  SUBTILIS  (Kiitz.)  Klercker,  1896,  p.  103;  Hazen,  1902, 
p.  162,   PI.   XXI,   figs.   10-13;    Ulothrix  subtilis  Wolle,  1887,  p. 
135,   PI.   CXVIII,  figs.  9  and   10,  in  part;  P.  B.-A.,  No.  614. 
Forming  extensive,   bright  green,  lubricous  masses  ;   filaments 
long,  cylindrical,  5-6.5  /j.  diam.,  rarely  8  /* ;  cells  1-3  diam.  long  ; 
wall  thin,  chromatophore  elliptical,  with  a  small  pyrenoid  ;  fila- 
ments  showing  little  tendency  to  break  up.     Greenland,  Me., 
Vt.  to  Pa.,  Cal.  Europe. 

Very  common  in  spring,  especially  where  water  is  running 
over  rocks  ;  also  in  watering-troughs  and  in  pools  ;  less  com- 
mon at  other  seasons. 

5.  S.  FLACCIDUS  (Kiilz.)  Gay,  1891,  p.  79,  PI.  XI,  figs.  101- 
106  ;  Hazen,  1902,  p.  164,  PI.  XXI,  figs.  14-17;  P.  B.-A.,  Nos. 
116,  1222;    Ulothrix  flaccida  Wolle,  1887,  p.    137,   PI.  CXVIII, 
figs.  27-28.     Filaments  rather  short,  forming  floccose  or  inter- 
woven  masses;    cells   6-9.5  f-  diam.,   somewhat   swollen,    %-\ 
diam.  long,  occasionally  up  to  2  diam.;  cell  wall  fairly  thick; 
chromatophore  broad,  with  a  large   pyrenoid.     On    wet    rocks 
and  soil,  and  on  the  bark  of  trees.     Mass.,  N.  Y.,  Cal.,  and 
probably  generally  distributed.  Europe. 

Only  slightly  larger  than  6".  stibtilis,  but  with  cells  usually 
shorter,  distinctly  swollen,  and  with  a  thicker  wall ;  a  plant  of 
moist  places  rather  than  submerged. 

6.  S.  FLUITANS  Gay,  1893,  p.  CLXXIV,  fig.  i  ;  P.  B.-A., 
No.  759;  Hazen,  1902,  p.  165,  PI.  XXII,  figs.  7-9.     Filaments 
yellowish  green,  crisped  and  interwoven,  sometimes  geniculate, 
with  a   strong  tendency  to  break  up,  6.5-9  /n  diam.,  cells  1-3 
diam.  long  ;  chromatophore  large  and  thick,  nearly  concealing 
the  inconspicuous  pyrenoid.     Mass.,  N.  J.  Europe. 

In  the  two  American  localities  this  species  occurs  on  smooth 
rocks  swept  by  rapid  water  from  a  cascade ;  the  filaments  are 
unaffected  by  the  current,  but  when  removed  to  quiet  water 
break  up  into  individual  cells  in  a  very  short  time. 

7.  S.  RIVULARIS  (Kiitz.)  Hazen,,   1902,   p.   166,   PI.  XXII, 
fig.  10-13;    Ulothrix  rivularis  Wolle,  1887,  p.  136,  PI.  CXVIII, 
figs.  6-8,  29-33.     Forming  bright  green  tufts  ;    filaments  some- 
what geniculate  but  not  easily  breaking  up,  8-n  n  diam.,  of  few 
cells  ;  giving  out  hooked  rhizoidal  branches  ;    cells  1-2  diam. 
long,    somewhat   swollen ;    chromatophore   orbicular  to  rhom- 


192  TUFTS  COLLEGE;  STUDIES,  VOL.  II,  No.  3 

boidal,   sharply  marked,  pyrenoid  large.     On  rock  or  earth  in 
rapid  streams.     N.  H.,  Conn.  Europe. 

Of  about  the  same  size  as  S.fluitans,  but  with  filaments  more 
distinctly  geniculate,  cells  less  easily  separable,  and  especially 
characterized  by  the  rhizoidal  branches. 

6.     MICROSPORA  Thuret,  1850,  p.  221. 

Filaments  simple,  usually  unattached  and  with  no  special 
basal  cell ;  chromatophore  a  granular  sheet  covering  the  cell 
wall  more  or  less  completely,  sometimes  with  perforations,  with- 
out pyrenoids  but  with  scattered  starch  granules.  Cell  wall 
composed  of  laminae,  so  arranged  that  when  the  filaments  break 
up  for  the  escape  of  zoospores,  the  pieces  remain  in  the  shape  of 
cylinders  open  at  both  ends,  with  a  cross  wall  near  the  middle, 
the  so-called  "H  section."  Asexual  reproduction  by  2- or  4- 
ciliate  zoospores,  i  or  2  in  a  cell ;  also  by  smaller  2-ciliate  zo- 
ospores, formed  several  in  a  cell ;  both  kinds  germinating 
directly  ;  whether  the  smaller  kind  may  also  act  as  gametes  is 
uncertain.  Aplanospores  and  akinetes  also  formed. 

A  widely  distributed  genus  of  fresh  water  algae,  formerly  in- 
cluded in  Conferva,  and  in  some  respects  allied  to  the  Hetero- 
kontae,  but  on  the  whole  nearer  to  the  Ulotrichaceae,  by  the 
form  of  the  chromatophore  and  the  chemical  nature  of  the  cell 
contents,  as  well  as  by  the  form  of  the  spores.  These  characters, 
however,  are  of  little  use  except  in  the  study  of  fresh  material. 

KEY  TO  THE  SPECIES  OF  MICROSPORA. 

i.     Cells  thick-walled.  2. 

i.     Cells  thin-walled.  5. 

2.     Cells  less  than  15  M  diam.  4.     M.  pachyderma. 

2.     Cells  16  M  diaiii.  or  more.  3. 

3.     Cells  distinctly  swollen.  3.     M.  Loefgrenii. 

3.     Cells  cylindrical  or  nearly  so.  4. 

4.     Cells  20  M  diam.,  1-2^  diam.  long.  5.     M.  Wittrockii. 

4.     Cells  21-25  M  diam.,  1-2  diam.  long.  2.     M.  amoena. 

4.     Cells  28-33  M  diam.,  1-2  diam.  long.  T-     M.  crassior. 

5.     Cells  ii  M  diam.  or  more.  6. 

5.     Cells  10  fj.  diam.  or  less.  7. 

6.     Cells  11-14  M  diam.               ,  7 .     M.  Willeana. 

6.     Cells  14-17  /j-  diam.  6.     M.floccosa. 

7.     Cells  5-7  M  diam.  10  .     M.  quadrata. 

7.     Cells  7-9.5  M  diam.  8. 

8.     Cells  cylindrical.  8.     M.  stagnorum. 

8.     Cells  slightly  constricted.  9.     M.tumidula^ 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  193 

1.  M.  CRASSIOR  (Hansg.)  Hazen,  1902,  p.  169,  PI.  XXIII,  fig. 
2;   P.  B.-A.,  No.  1070;   M.  amocna  forma  crassior  Wille,  1899, 
p.  149.     Filaments  long,  dark  green,  nearly  cylindrical,  28-33  /* 
diam.,  cells  1-1.6  diam.  long,  with  wall  2.5-3  M  thick  ;  lamellate 
structure  usually  distinct ;  chromatophore  dense,  covering  the 
whole  cell  wall  and  hiding  the  large  nucleus. 

The  largest  species  of  the  genus,  the  nearest  species,  M. 
amocna,  being  considerably  smaller,  with  thinner  walls  and  rela- 
tively shorter  cells.  It  forms  thick  tangled  masses  in  rapid 
brooks,  from  May  to  October.  Mass,  to  N.  Y.  Europe. 

2.  M.  AMOENA  (Kiitz.)  Rabenhorst,   1868,  p.  321  ;   P.  B.-A., 
No.  igb  as  Ulothrix  zonata,  No.  616  ;   Hazen,  1902,  p.  170,  PI. 
XXIII,  fig.  i  ;   Conferva  amocna  Wolle,  1887,  p.  140,  PI.  CXXI, 
figs  1-5.     Filaments  long,  dark  or  bright  green,  nearly  cylindri- 
cal,  21-25  P-  diam-;  cells   1-2  diam.  long,  with  wall  about  2  /A 
thick  ;  chromatophore  dense,  covering  the  whole  cell  wall,  and 
hiding  the  quite  large  nucleus.     In  rapid  brooks,  forming  more 
or  less  tangled,  often  quite  long  masses,  April  to  July.     Mass, 
to  N.  J.  Europe. 

3.  M.    LOEFGRENII    (Nordst.)   Lagerheim,    18873,  p.  417  ; 
Hazen,    1902,   p.    171,    PI.   XXIII,   figs.   3  and  4;  Wittr.  and 
Nordst.,  Alg.  Exsicc.,  No.  17.     Filaments  long,  16-20  //.  diarn., 
cells  distinctly  swollen,  1-2  diam.  long,  wall  about  2.5  /x  thick  ; 
chromatophore  dense,  covering  the  whole  cell  wall,  concealing 
the  nucleus.     N.  Y.,  Mass.  Europe,  So.  America. 

Smaller  than  M.  amoena,  and  with  distinctly  swollen  cells ; 
but  otherwise  of  the  same  character  as  that  species  and  M.  cras- 
sior. 

4.  M.    PACHYDERMA   (Wille)    Lagerheim,    18873,    p.    415; 
Conferva  pachyderma   Wille,    1881,   p.    13,    PI.   IX,   figs.  28-35. 
Filaments  8-14  -p.  diam.,  cells  1^-3  diam.  long,  wall  up  to  3  /*. 
thick ;   akinetes  rounded-quadrate  to  ellipsoid,  not  larger  than 
the  vegetative  cells.     Greenland.  Europe. 

5.  M.    WITTROCKII   (Wille)    Lagerheim,     18873,    p.    417 ; 
Hazen,  1902,  p.  172,  PI.  XXIII,  figs.  5-7;  Wittr.  and  Nordst., 
Alg.  Exsicc.,  No.  422.     Filaments  long,  silky,  light  green,  per- 
fectly cylindrical,  about  20  //.  diam.;  cells  1-2^  diam.  long,  wall 
about  1.5  /i  thick,  not  distinctly  lamellate;  chromatophore  thin, 
often  perforated,  or  not  occupying  the  full  length  of  the  cell,  the 
large  nucleus  usually  quite  distinct.     Vermont,  Mass.,  N.  Y. 

Europe. 

A  more  delicate  plant  than  any  of  the  preceding  species  and 
apparently  common  in  early  spring,  often  in  company  with  M. 
stagnorum. 


194          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

6.  M.  FLOCCOSA  (Vauch.)  Thuret,   1850,  p.  222,  PI.  XVII, 
figs.  4-7;   Hazen,    1902,  p.  173,  PI.  XXIV,  figs.  1-4;   P.  B.-A., 
No.  864.     Conferva  floccosa  Wolle,  1887,  p.  140,  PI.  CXX,  figs. 
21-25.     Filaments  bright  or  yellowish  green,  cylindrical  or  very 
nearly  so,  14-17  (rarely  18)  /ndiam.;  cells  f-2^4  diam.  long,  with 
thin  walls  ;  chromatophore  pale  green,  often  perforated  or  in  net 
form  ;  akinetes  18-22  /x'diam.,  sphaeroidal,  cuboidal  or  subcylin- 
drical.     Fig.  68.     Mass,  to  N.  J.,  Vancouver  I.  Europe. 

A  very  common  spring  plant,  forming  loose  floccose  masses  in 
slow  streams  and  quiet  waters. 

7.  M.  WILLEANA   Lagerheim   in   De   Toni,    1889,   p.   228; 
Hazen,  1902,  p.  175,  PI.   XXIV,  figs.  5-7;   P.  B.-A.,  Nos.  619, 
1326.     Filaments  cylindrical,   light  green,  11-14  /A  diam.;  cells 
y^-\y-2,    (rarely  2)  diam.   long,   wall  thin  ;  chromatophore  vari- 
able, but  usually  denser  than  in  M.floccosa;  akinetes  14-16.5  p. 
diam.,  spherical  to  subcylindrical.     Mass,  to  N.  J.,  Alaska,  Cal. 

Europe. 

Occurring  in  the  same  localities  as  M.floccosa,  and  much  re- 
sembling the  latter,  but  with  somewhat  smaller  filaments  and 
decidedly  smaller  akinetes. 

8.  M.    STAGNORUM    (Kiitz.)    Lagerheim,     1887  a,     p.    417; 
Hazen,  1902,  p.  176,  PL  XXIV,  figs.  12-13;   P-  B.-A.,  No.  618. 
Filaments  cylindrical,  7.5-9.5  (usually  8) /*  diam.,  cells  1-3  diam. 
long,  wall  thin  ;  chromatophore  not  dense,  and  often  occupying 
only  the  middle  part  of  the  cell.     Greenland,  Maine  to  N.  J. 

Europe,  So.  America. 

A  common  species  of  early  spring,  but  occurring  also  in 
summer  and  autumn,  often  in  company  with  other  species  of 
Micro spora  or  Ulothrix. 

9.  M.  TUMIDULA  Hazen,  1902,  p.  177,  PI.  XXIV,  figs.  8-n  ; 
P.  B.-A.,  Nos.  1025,  1277.    Filaments  with  distinct  constrictions 
at    the    dissepiments,   6.7-9.5  (usually   7.5)  ^  diam.  ;    cells   1-2 
diam.  long ;  chromatophore  rather  dense,  nearly  or  quite  cover- 
ing the  cell  wall ;  akinetes  8-n  p.  diam.,  spherical  or  flattened. 
Greenland,  Mass.,  to  N.  J.,  also  at  Banff,  Canada. 

Forming  dull  green  skeins  or  floccose  masses  in  brooks  and 
pools  ;  much  like  M.  stagnorum,  from  which  it  is  distinguished 
by  the  distinctly  contracted  dissepiments  and  the  more  uniform 
chromatophore. 

10.  M.  QUADRATA  Hazen,  1902,  p.  178,  PI.  XXIV,  figs.  14 
and  15;   P.  B.-A.,  No.  1276.     Filaments  light  green,  perfectly 
cylindrical,  5.5-7  /x  diam.  ;  cells  ^-i  diam.  long,  with  very  thin 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  195 

wall ;  chromatophore  a  fine  even  coating  over  all  the  cell  wall, 
often  including  the  dissepiments.  Vermont  and  Mass,  to  N.  Y. 
Forming  light  green  floccose  masses,  in  still  or  slow  water  ; 
has  been  collected  from  May  to  October,  which  would  seem  to 
indicate  less  of  a  spring  plant  than  most  species  of  Microspora. 
Its  very  fine  filaments  with  short  cells  distinguish  it  quite 
clearly  from  our  other  species. 

Family  2.     ULVACEAE. 

Membranaceous,  plane,  or  tubular  fronds ;  cells  uninucleate, 
with  disk-shape  chromatophore  and  one  pyrenoid  ;  asexual  re- 
production by  4-ciliate  zoospores  (sometimes  biciliate  ?)  ;  sexual 
reproduction  by  biciliate  gametes. 

The  membrane  is  in  the  form  of  a  tube,  a  sac,  or  a  flat  expan- 
sion ;  in  the  latter  case  it  may  consist  of  one  or  two  layers  of 
cells  ;  in  the  simplest  forms  there  may  be  merely  two  rows  of 
cells  side  by  side,  or  in  some  parts  of  the  frond,  only  a  single 
series  of  cells.  Spores  and  gametes  may  be  formed  in  any  cell 
of  the  frond  except  the  lowest  cells,  which  may  send  down 
rhizoidal  prolongations,  uniting  to  form  a  stipe. 

Of  world-wide  distribution  ;  marine,  rarely  fresh  water  plants  ; 
usually  gregarious,  often  growing  in  great  quantities.  They 
are  specially  plants  of  the  literal  zone,  occasionally  extending 
down  for  a  short  distance  into  the  sublitoral. 

KEY  TO  THE  GENERA  OF  UI/VACEAE. 

i.     Frond  tubular,  rarely  of  one  or  two  series  of  cells.  2. 

i.     Frond  tubular  only  in  the  early  stages,  if  ever.  3. 

2.     Frond  gelatinous  ;  cells  in  loosely  united  longitudinal  series. 

2.    ILEA. 
2.     Not  specially  gelatinous;  membrane  parenchymatous. 

i.    ENTEROMORPHA. 

3.     Minute  ;  adherent  by  the  entire  lower  surface.      5.     PROTODERMA. 

3.     Larger;  adherent  only  at  the  base.  4. 

4.     Frond  of  a  single  layer  of  cells.  3.     MONOSTROMA. 

4.     Frond  of  two  layers  of  cells.  4-     UI/VA. 

i.     ENTEROMORPHA  Link,  1820,  p.  5. 

Frond  originating  in  a  single  series  of  cells,  which  by  re- 
peated division  form  a  tubular  frond,  the  membrane  of  which 
consists  of  a  single  layer  of  cells  ;  in  some  of  the  simpler  species 
the  tubular  stage  is  not  reached,  and  the  frond  in  the  adult 
state  consists  of  two  or  a  few  series  of  cells,  united  without  any 


196          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

interior  space.  All  the  cells  of  the  frond,  except  the  lowest, 
capable  of  producing  zoospores  or  gametes,  which  are  dis- 
charged through  an  opening  in  the  cell  wall. 

A  large  genus,  connected  with  Ulva  by  E.  linza,  in  which 
the  tube  is  compressed,  and  the  membranes  united  in  the 
median  part ;  on  the  other  hand,  Monostroma  grocnlandicum  is 
hardly  to  be  distinguished  from  some  of  the  simple  filiform 
species  of  Enteromorpha.  E.  intestinalis  is  found  the  whole 
world  over,  and  other  species  are  very  widely  distributed.  They 
are  found  not  only  in  the  sea,  but  about  salt  springs  and  salt 
mines ;  they  abound  in  brackish  water,  and  are  occasionally 
found  in  quite  fresh  water. 

At  places  wht^  the  salinity  of  the  water  is  subject  to  much 
change,  very  perplexing  forms  occur ;  specimens  collected  near 
the  salt  mines  at  Syracuse,  N.  Y.,  show  in  the  same  frond  char- 
acters of  E.  compressa,  E,  crinita,  and  E.  marginata.  It  is  impos- 
sible to  say  what  is  the  normal  form ;  the  specimens  must  be 
considered  as  teratological.  Specimens  from  Great  Salt  L/ake, 
Utah,  also  show  abnormal  forms. 

KEY  TO  THE  SPECIES  OF  ENTEROMORPHA. 
i.     Frond  flat,  the  membranes  free  at  the  margins,  but  united  between. 

19.     E,     linza. 

i.     Frond  of  one  to  a  few  series  of  cells,  not  tubular.  2. 

i.     Frond  tubular.  3. 

2.     Frond  simple.  i.     E.percursa. 

2.     Frond  branched.  2.     E.  cruciata. 

3.     Cells  not  arranged  in  longitudinal  series  except  in  the  very  youngest 

parts.  4. 

3.     Cells  more  or  less  in  longitudinal  series,  usually  in  the  greater  part 

of  the  frond.  9. 

4.     Cells  of  the  new  generation  in  twos,  threes  and  fours,  in  the  wall 

of  the  mother  cell.  16.     E.  fascia. 

4.     Mother  cell  wall  not  persisting  after  division.  5. 

5.     Frond  with  short,  spine-like  ramuli,  in  addition  to  branches. 

8.     E.  acanthophora. 

5.     Frond  with  more  or  less  plentiful  branches.  6. 

5.     Frond  simple  or  with  a  few  proliferations.  7. 

6.     Frond  with  flattened  rachis  branching  from  the  margin. 

17.     E.  micrococca  var.  subsaha. 

6.     Frond  filiform  ;  branches  with  contracted  base,  expanding  upwards. 

10.     E.  compressa. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  197 

7.     Cells  10-16  /u,  diain. ;  fronds  usually  inflated  and  constricted  ;  often  of 

large  size.  18.     E.  intestinalis. 

7.     Cells  4-8  /x  diam. ;  fronds  usually  short.  8. 

8.     Membrane  8-10  M  thick  ;  cells  5-7  M  diam.  n.     E.  minima. 

8.     Membrane  15-20  /*  thick  ;  cells  4-5  /u,  diam.         17.     E.  micrococca. 

9.     Fronds  simple,  inflated  and  flexuous.  15.     E.flexuosa. 

9.     Fronds  simple  or  with  occasional  proliferations  ;  not  inflated.     10. 

9.     Fronds  regularly  branched.  u. 

10.     Frond  narrowly  linear,  strongly  compressed. 

13.     E.  marginata. 
10.     Frond  filiform,  2-8  cells  wide,  tubular  only  in  the  widest  parts ; 

branches  two  cells  wide.  3.     E.  torta. 

10.     Frond  filiform,  tubular,  of  uniform  diameter;  of  numerous  series 

of  squarish  cells.  14.     E.  prolifera  var.  tubulosa. 

ii.     Frond  beset  with  numerous  thorn-like  branches. 

12.     E.  salina  var.  polyclados. 
ii.     Branches  proliferous,  similar  to  main  filaments. 

14.     E,  prolifera. 

u.     Branches  of  successive  orders,  tapering  from  base  to  apex.          12. 
12.     Chromatophore  filling  cell.  13. 

12.     Chromatophore  not  filling  cell,  giving  a  net-like  appearance. 

14. 
13.     Ultimate  ramuli  short,  spine-like,  not  monosiphonous. 

9.     E.  ramulosa. 

13.     Ultimate  ramuli  of  a  single  series  of  cells.  6.     E.  crinita. 

13.     Ultimate   ramuli    polysiphonous,    of  a   few   symmetrically  placed 

series  of  cells.  7.     E.  erecta. 

14.     Ultimate  ramuli  of  a  single  series  of  cells.  4.     E.plumosa. 

14.     Ultimate  ramuli  not  of  a  single  series  of  cells. 

5.     E.  clathrata. 

i.  E.  PERCURSA  (Ag.)  J.  G.  Agardh,  1842,  p.  15  ;  P.  B.-A., 
Nos.  469,  968  ;  Tetranerna  percursum  Areschoug,  1846,  p.  192,  PI. 
II. A.  Frond  filiform,  in  the  earliest  state  of  one  row,  afterwards 
of  two  rows  of  cells,  placed  symmetrically  side  by  side ;  cells 
10-15  p.  wide,  from  once  to  twice  as  long.  Greenland  to  N.  J.  ; 
Alaska  to  Cal.  Europe. 

A  common  species,  forming  masses  in  upper  tide  pools,  and 
in  ditches  in  marshes,  etc.  It  often  grows  in  company  with 
other  species,  but  is  easily  distinguished  on  microscopic  exam- 
ination by  th'e  double  row  of  cells,  usually  in  exact  symmetry, 
side  by  side.  The  small  chromatophores  occupy  only  part  of 
the  cell  room,  giving  the  same  net-like  appearance  found  in  E. 
clathrata. 


198  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

2.  E.  CRUCIATA  Collins,  1896,  p.  3  ;  1903,  p.  27,  PI.  XLIII, 
fig.  i  ;  P.  B.-A.,  No.  222.  Frond  filiform,  branching,  mostly 
of  a  single  series  of  cells,  but  at  the  points  of  branching  often  of 
two  or  more  series ;  branches  issuing  at  right  angles  or  nearly 
so,  usually  opposite  but  sometimes  alternate  or  secund,  simple, 
usually  short,  tapering  ;  monosiphonous  portions  20-30  /u,  diam- 
eter ;  cells  about  as  long  as  broad,  cell  wall  thick;  in  the 
irregular  masses,  where  several  branches  issue  near  together, 
the  cells  are  rounded  and  sometimes  reach  a  diameter  of  50  /j.. 

This  plant  is  very  different  from  other  species  of  Enteromor- 
pha,  the  nearest  being  E.  percursa  ;  but  E.  cruciata  has  nothing 
of  the  symmetry  and  uniformity  that  especially  characterize 
E.  percursa.  The  monosiphonous  parts  with  few  and  short 
branches  remind  one  somewhat  of  Rhizoclonium,  but  the 
branches  are  often  of  many  cells,  and  wherever  several 
branches  issue  near  the  same  point,  an  irregular  mass  of 
cells  is  formed.  It  was  found  in  a  lagoon  at  Eagle  Island, 
Penobscot  Bay,  Maine,  connecting  with  the  sea  only  at  excep- 
tionally high  tides,  in  floating  masses  in  company  with  Clado- 
phora  expansa,  Lyngbya,  etc.,  in  July,  1894,  and  is  not  known 
elsewhere. 

3.  E.  TORTA  (Mert.)  Reinbold,  1893,  P-  2°i  >'  P-  B.-A.,  No. 
223.     Frond  filiform,  compressed,  simple  or  with  occasional  long 
proliferous  branches,  which  usually  consist  of  only  two  rows  of 
cells ;  cells  rectangular,  always   in  longitudinal   and  mostly  in 
cross  series.     Me.,  Barbados.  Europe. 

A  very  slender  species,  the  main  filaments  only  2-8  cells  wide, 
and  only  in  the  wider  forms  showing  any  open  space  within. 
The  branches  are  few,  at  wide  angles,  and  are  seldom  over  two 
cells  wide.  They  resemble  somewhat  the  fronds  of  E.  percursa, 
but  the  cells  in  the  latter  are  more  symmetrically  arranged  ;  and 
E.  percursa  is  always  simple  and  never  has  over  two  rows  of 
cells,  as  do  most  of  the  older  parts  of  this  plant. 

4.  E.  PLUMOSA  Kiitzing,   1843,   p.  300,  PL  XX,  fig.  i  ;  E. 
Hopkirkii   Harvey,    1849-51,    PI.    CCL,XIII ;    1858,    p.    58;    P. 
B.-A.,   No.   463;    Ulva  Hopkirkii  Farlow,    1881,   p.*  44.     Frond 
filiform,    cylindrical    or   somewhat    compressed,     very    slender 
and    delicate,    much    and    repeatedly    branched,    the   branches 
tapering  and  ending  in  a  single  series  of  cells  ;  cells  about  8  p. 
wide  in  the   monosiphonous   part,   below  about   12  X  20  /*,  with 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  199 

quite  small  chromatophores  ;   always  in  longitudinal  and  often 
in  transverse  series.     Me.  to  W.  I.  l:.nrope. 

One  of  the  most  attractive  of  our  Enteromorphas  both  in  habit 
and  microscopically.  There  are  other  species  which  occasion- 
ally have  short  mouosiphonous  branches,  but  in  E.  plumosa 
nearly  every  young  branch  terminates  in  a  monosiphonous  series 
of  considerable  extent.  Common  in  northern  New  England, 
growing  largely  on  Cladophora  glauccsccns  and  on  rocks  and 
shells  in  rock  pools ;  also  in  quiet  bays. 

5.  E.  CLATHRATA  (Roth)  Greville,  1830,  p.  181  ;   P.  B.-A., 
No.  LXXVIII ;    Ulva  clathrata  Farlow,  1881,  p.  44.     Frond  fili- 
form, cylindrical  or  compressed,  much  branched  in  all   direc- 
tions, the  branches  tapering  from  base  to  summit,  but   not  end- 
ing in  a  single  series  of  cells  ;  cells  rectangular,  usualty  longer 
than   broad,  always  in  longitudinal  series,   the  chromatophore 
noticeably  smaller  than  the  cell.     Me.  to  W.  I.;  Alaska. 

Europe,  Tasmania,  New  Zealand. 

A  species  of  warm  quiet  waters,  where  it  often  forms  great 
floating  masses ;  it  differs  from  most  other  species  in  having  a 
real  system  of  branching  of  various  orders  ;  also  in  the  chroma- 
tophore smaller  than  the  cells.  From  E.  plumosa,  which  agrees 
with  it  in  these  particulars,  it  differs  by  the  absence  of  mono- 
siphonous ramuli.  It  is  common  at  some  points  in  southern 
Mass.,  and  probably  along  the  coast  to  the  south  ;  but  so  many 
forms  have  been  included  under  this  name  in  older  records,  that 
few  localities  are  certain.  It  is  not  common  north  of  Cape  Cod. 
Ulva  clathrata  var.  Rothiana  forma prostrata  Farlow,  1881,  p.  44, 
P.  B.rA.,  No.  459,  seems  nearer  to  E.  prolifera. 

6.  E.  CRINITA  (Roth)  J.  G.  Agardh,  1882,  p.  144  ;  P.  B.-A., 
Nos.  460,  965,  1325.     Frond  filiform,  cylindrical  or  compressed, 
much   and   repeatedly   branched,    the   branches   tapering,    the 
smallest  usualty  of  a  single  series  of  quite  short  cells  ;  cells  al- 
most   always   in    longitudinal   series,   often  rounded,   quite  or 
nearly  filled  by  the  chromatophore.     Me.  to  N.  J.;  Gulf  of  Mex- 
ico, Alaska  to  Cal.  Jtttropc. 

In  habit  this  common  marine  species  resembles  E.  clathrata, 
but  the  latter  lacks  the  short-celled  monosiphonous  ramuli  ; 
monosiphonous  ramuli  are  found  in  E.  plumosa,  but  the  net- like 
cells  of  the  latter  are  quite  distinct  from  the  cells  of  E.  crinita, 
which  resemble  those  of  E.  prolifera,  though  somewhat  smaller. 


200     TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

The  material  distributed  as  P.  B.-A.,  No.  1325,  was  from  a 
station  once  connected  from  the  sea,  but  cut  off  for  several 
years,  the  water  becoming  quite  fresh.  The  Enteromorpha 
grew  in  company  with  species  of  Oedogonium,  Spirogyra,  and 
other  fresh  water  genera,  and  was  as  abundant  as  ever,  the  only 
noticeable  change  being  a  greater  development  of  the  mono- 
siphonous  part  in  proportion  to  the  rest. 

7.  E.    ERECTA    (L,yng.)   J.    G.    Agardh,    1882,    p.    152  ;    P. 
B.-A.,   No.  461.     Frond  filiform,  with  numerous  long,  usually 
erect  branches,  more  slender  than  the  main  filament ;  the  ulti- 
mate ramuli  of  varying  length,  polysiphonous,  the  cells  being 
symmetrically  arranged  in  successive  segments,  similar  to  those 
of  Polysiphonia ;  cells  in  the  main  stem  and   branches  in  longi- 
tudinal and  usually  in  transverse  series.    Fig.  70.    Me.  to  W.  I. 

Europe. 

The  most  distinctive  character  of  this  species  is  found  in  the 
polysiphonous  ramuli ;  in  habit  it  is  not  unlike  E.  crinita,  but 
the  cells  of  E.  erecta  are  usually  more  symmetrically  arranged 
in  the  older  parts  of  the  frond,  and  more  rectangular.  It  is  not 
uncommon  as  a  plant  of  exposed  shores. 

8.  E.  ACANTHOPHORA  Kiitzing,  1849,  p.  479;   1856,  p.  12, 
PI.  XXXIV,  fig.. i  ;  P.  B.-A.,   No.  515.     Frond  more  or  less 
proliferously  branched,  the  branches  usually  somewhat  enlarged 
upwards,  beset  with  numerous  short,   spine-like  ramuli,   with 
broad  base   and  acute  tip  ;  cells  6-8  /x  diam.,  roundish  angular, 
showing  no  longitudinal  arrangement  except  indistinctly  at  the 
tips  of  the  ramuli ;  marine  and  fresh  water.     Cal.,  at  shore,  and 
in  mountains  up  to  300  meters.  So.  America,  New  Zealand. 

Somewhat  resembles  E.  ramulosa,  but  the  cells  are  .much 
smaller,  with  hardly  any  indication  of  longitudinal  arrangement ; 
the  substance  is  less  firm,  and  the  color  is  lighter.  The  fronds 
seem  to  collapse  irregularly  in  drying.  The  spine-like  ramuli 
vary  in  abundance,  sometimes  almost  covering  the  frond  ;  the 
regular  branches  are  not  very  numerous,  and  seem  quite  dis- 
tinct from  the  ramuli. 

9.  E.   RAMULOSA  (Eng.   Bot.)  Hooker,   1833,  p.  315;  Har- 
vey,   1849-51,   PI.  CCXL,V  ;    Ulva  clathrata  var.  ramulosa  Far- 
low,  1881,  p.  44.     Frond  tubular,  rather  stiff,  much  branched; 
branches  with  short,  spine-like  ramuli  ;  cells  rather  rounded, 
showing   longitudinal    series   only    in   the    ultimate   divisions. 
Mass,  to  W.  I.  Europe,  New  Zealand,  Australia. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  201 

A  coarse  species,  readily  recognized  by  its  habit.  It  appears 
to  be  not  uncommon  on  the  southern  part  of  the  Atlantic  coast, 
but  rare  in  New  England.  The  color  is  usually  a  rather  deep 
or  dark  green ;  the  main  branches  are  quite  long,  and  are 
everywhere  beset  with  short,  tapering  ramuli  ;  the  cells  are 
rounded,  almost  entirely  occupied  by  the  chromatophore  ;  with- 
out any  definite  arrangement,  except  in  the  ramuli. 

10.  E.  COMPRESSA  (L.)  Greville,   1830,  p.  180,  PI.  XVIII. 
Frond  tubular,  more  or  less  compressed,  sometimes  constricted, 
varying  much  in  dimensions ;  branches  usually  simple,  cylin- 
drical or  expanding  above,  in  either  case  narrowed  at  the  base, 
similar  in  appearance  to  the  main  stem  ;  cells  in  no  definite 
order;    membrane  rather  thin.     Greenland  to  N.  J.;  Alaska  to 
Cal.  Europe,  So,  America,  Tasmania. 

A  variable  species,  but  now  understood  in  a  narrower  sense 
than  formerly,  and  including  only  forms  with  branches  con- 
tracted at  the  base,  with  cells  10-15  /j.  diam.,  arranged  in  no 
definite  order,  and  with  membrane  not  thickened. 

Forma  SUBSIMPLEX  J.  G.  Agardh,  1882,  p.  137;  P.  B.-A., 
No.  964.  Frond  hardly  branched,  of  uniform  diameter.  Me. 

Europe. 

11.  E.  MINIMA  Nageli  in   Kiitzing,    1849,  p.  482  ;   1856,  p. 
16,  PI.  XLIU,  fig.   3;  P.  B.-A.,   Nos.  468,  912.     Frond  i-io 
cm.  long,  1-5  mm.  broad,  simple  or  slightly  proliferous,  soft  and 
delicate,    membrane   8-10  /u.  thick,  cells  angular,  5-7  p.  diam., 
arranged  in  no  definite  order.     Greenland  to  Conn.;  Alaska  to 
Mexico.  Europe,  So.  Pacific. 

A  small  species,  resembling  E.  compressa,  but  smaller  in  di- 
mensions of  fronds  and  size  of  cells.  It  is  probably  common, 
but  is  easily  overlooked  among  the  larger  and  better  known 
species  of  the  genus.  The  extreme  thinness  of  the  frond  gives 
it  a  very  soft  and  delicate  feeling  to  the  touch,  which  is  the  best 
character  by  which  to  recognize  it  when  growing.  It  seems  to 
grow  mostly  in  the  lower  half  of  the  literal  zone. 

Forma  RIVULARIS  Collins,  P.  B.-A.,  No.  XXVI.  Color  pale, 
fronds  to  half  a  meter  in  length,  substance  more  delicate  than  in 
the  type.  These  differences  are  probably  due  to  its  place  of 
growth,  running  fresh  water.  Alaska. 

Forma  GLACIAUS  Kjellman,  1877,  p.  50;  P.  B.-A.,  No. 
1183.  Frond  9-13^  thick;  cells  5-8  p.  diam.;  forming  a  dense 


202  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

coating  on  rocks  covered  only  at  high  tide,  and  at  other  times 
wet  with  water  from  melting  ice.     Greenland  ;  Mass. 

The  habitat  given  with  the  description  is  that  of  the  original 
arctic  locality ;  the  Mass,  specimens  agree  with  the  Greenland 
plant,  though  growing  in  summer,  free  from  glacial  conditions. 

12.  E.    SAUNA  Kiitzing,    1845,    p.   247;    1856,    p.    13,   PI. 
XXXVI,  fig.  r  ;  P.  B.-A.,  No.  659.     Frond  filiform,   tubular, 
with  a  few  branches,  which  are  sometimes  opposite,  of  two  or 
more  rows  of  cells,  or  in  the  youngest  of  a  single  series ;  cells 
quadrangular,  14-16  p.  square,  or  slightly  longer  than  broad,  in 
longitudinal  series  throughout ;  membrane  thickened  on  both 
sides.     Fla.,  Louisiana.  Europe- 

The  slender  fronds  with  relatively  large  cells  in  longitudinal 
series  distinguish  this  species  with  tolerable  distinctness  from 
any  others  within  our  limits. 

Var.  POLYCLADOS  Kiitzing,  1845,  p.  248;  E.  poly  dados  Kiit- 
zing, 1856,  p.  13,  PI.  XXXVI,  fig.  2.  Filaments  beset  with 
more  or  less  numerous  short,  horizontal,  spine-like  rarnuli. 
Florida. 

13.  E.    MARGINATA  J.   G.   Agardh,    1842,  p.  16 ;   Kiitzing, 
1856,  p.   15,  PI.  XLJ,  fig.   i;  P.  B.-A.,  No.  466.     Frond  fili- 
form, compressed,  simple  or  with  a  few  proliferous  branches ; 
cells  4-8  p.  diam.,  squarish,  arranged  in  longitudinal  series,  very 
distinctly  in  the  two  or  three  rows  at  each  side,  less  so  on  the 
middle  portion.     Me.  to  N.  J.  ;  Great  Salt  Lake,  Utah;  Cal. 

Europe. 

A  small  species  and  apparently  not  common,  occuring  mostly 
on  stems  and  roots  of  Spartina,  etc.  The  color  is  usually  quite 
a  deep  green  ;  the  fronds  are  comparatively  narrow,  seldom  over 
15-20  cells  wide,  and  the  width  continues  quite  uniform  through- 
out a  filament,  the  margin  being  straight  and  even.  Usually 
the  fronds  are  simple,  but  occasionally  one  finds  a  few  prolifer- 
ous branches. 

14.  E.  PROLIFERA  (Fl.  Dan.)  J.  G.  Agardh,    1882,  p.  129, 
PI.  IV,  figs.  103  and  104;  P.  B.-A.,  Nos.  470,610,  913.     Frond 
up  to  several  meters  long  and  2  cm.  diameter,  tubular  or  com- 
pressed,   with   more    or    less   abundant    proliferous   branches, 
which   are   usually   simple,    but  sometimes    also    proliferous ; 
branches  varying  much  in  length  and  diameter;  cells  10-12 /A, 
in  the  younger  parts  always  arranged  in  longitudinal  series, 
which  become  less  distinct  in  the  older  parts;  membrane  15-18 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  203 

/A  thick,  not  much  exceeding  the  dimensions  of  the  cells  in  cross 
section.     Greenland  to  W.  I.  ;   Alaska  to  Cal.  Europe. 

A  common  species,  formerly  included  in  E.  compressa  or  E. 
intestinalis,  to  the  former  of  which  it  is  most  allied,  but  from 
which  it  differs  in  the  longitudinally  seriate  cells,  very  manifest 
in  the  younger  portions,  and  disappearing  only  in  the  quite  old 
parts.  In  habit  it  is  very  variable,  from  slender,  slightly 
branched  forms,  only  a  few  cm.  long,  to  richly  and  repeatedly 
branched  fronds ;  branches  sometimes  long  and  slender,  some- 
times short  and  very  densely  set,  sometimes  long  and  short 
intermingled  quite  without  order.  It  appears  to  prefer  some- 
what sheltered  localities  where  it  is  not  left  bare  for  any  consid- 
erable time  at  low  tide.  It  is  found  in  fresh  water  in  several 
stations  in  the  western  states,  as  well  as  about  salt  springs. 

Var.  arctica  (J.  Ag.)  nov.  comb.  ;  E.  arctica].  G.  Agardh, 
1882,  p.  124,  PI.  IV,  figs.  100-102.  Cells  smaller  and  rounded, 
membrane  20-30/1  thick,  cells  10-14  p.  in  cross  section,  usually 
longer  than  broad,  sometimes  double  their  breadth.  Green- 
land. Spitsbergen. 

Var.  TRABECULATA  Rosenvinge,  1893,  p.  961,  fig.  55.  More 
slender  than  the  type,  with  long,  capillary  branches ;  the  cen- 
tral cavity  traversed  by  transverse  and  oblique  "  trabeculae." 
Greenland. 

Var.  TUBULOSA  (Ku'tz.)  Reinbold,  1889,  p.  117;  P.  B.-A., 
No.  471.  E.  tubulosa  Kiitzing,  1856,  p.  n,  PI.  XXXII,  fig.  2. 
Slender,  slightly  branched,  of  nearly  uniform  diameter  through- 
out. In  ditches  in  marshes.  Mass.  ;  Great  Salt  Lake,  Utah  ; 
reported  from  Barbados.  Europe. 

15.  E.  FLEXTJOSA  (Wulf.)  J.  G.  Agardh,  1882,  p.  126; 
P.  B.-A.,  No.  462.  Frond  cylindrical,  tubular,  simple,  taper- 
ing to  a  filiform  stipe  below,  above  inflated,  flexuous  and  intes- 
tine-like ;  cells  6-8X8-12  /*,  roundish  polygonal,  in  longitudinal 
series  ;  membrane  somewhat  thickened  on  the  inside  ;  chro- 
matoph'ore  filling  the  thick- walled  cell.  Fla.,  Southern  Cal. 

Warmer  waters  generally. 

This  is  a  southern  species,  and  on  our  Florida  shores  appears 
to  take  the  place  of  E.  intestinalis  in  the  north.  From  the  latter 
it  differs  in  having  somewhat  smaller  cells,  arranged  in  regular 
series  ;  also  somewhat  more  delicate  membrane.  From  E.  com- 
pressa it  is  also  distinguished  by  the  arrangement  of  the  cells, 


204  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

and  its  habit  is  dissimilar  ;  from  both  these  species  it  differs  in 
having  a  thicker  wall  between  the  cells. 

16.  E.   FASCIA   Postels  and  Ruprecht,   1840,  p.   21  ;   Wittr. 
and  Nordst.,  Alg.  Exsicc.,  No.  1052.     Frond  elongate,  tubular- 
compressed,  from  a    slender   stipe ;    sparingly  branched ;    cells 
4-6X6-8  /u,,  roundish  angular,  in  no  apparent  order,  often  con- 
taining 2-4  daughter  cells.     Behring  Sea. 

In  the  form  of  the  frond  not  unlike  E.  intestinalis,  but  with 
a  different  arrangement  of  cells,  somewhat  recalling  Ilca  fnlves- 
cens.  The  latter,  however,  is  much  softer  and  more  gelatinous, 
and  the  cells  are  arranged  in  longitudinal  series,  and  more  sym- 
metrical in  all  respects.  The  characteristic  arrangement  of 
cells  is  not  always  distinct,  and  in  its  absence  the  species  is  dis- 
tinguished from  E.  intestinalis  chiefly  by  the  smaller  cells.  Can 
hardly  be  considered  a  well  established  species. 

17.  E.  MICROCOCCA  Kutzing,  1856,  p.  u,  PI.  XXX,  fig.  2  ; 
P.  B.-A.,  No.  66.     Fronds  1-5  cm.  long,  1-5  mm.  wide,  tubular 
or  compressed,  simple  or  slightly  proliferous,  much  curled  and 
twisted  ;  cells  angular,  4-5  p.  diam.,  in  no  definite  order  ;  thick- 
ness of  membrane,   15-20/1..      Greenland  to  Mass.;  Alaska   to 
Mexico.  Europe. 

The  smallness  of  its  cells  distinguishes  it  from  all  our  species 
but  E.  minima,  in  which  the  dimensions  are  only  slightly 
larger ;  but  the  latter  species  has  a  very  thin  and  delicate 
membrane,  while  in  E.  micrococca  it  is  relatively  quite  thick, 
the  thickening  being  specially  pronounced  on  the  inner  side  ; 
this  gives  it  a  coarser  feeling  to  the  touch  than  E.  minima.  Its 
favorite  habitat  on  the  New  England  coast  appears  to  be  on  the 
surface  of  shaded,  steep  or  vertical  cliffs,  especially  where  the 
flow  or  drip  of  fresh  water  keeps  it  continually  moist. 

Forma  BULLOSA  Collins,  P.  B.-A.,  No.  1067.  Fronds  large, 
irregularly  inflated,  to  5  cm.  diam.  Habit  of  E.  intestinalis 
forma  maxima,  but  structure  of  E.  micrococca.  Cal. 

Forma  SUBSALSA  Kjellman,  1883,  p.  292,  PI.  XXXI,  figs. 
1-3;  P.  B.-A.,  Nos.  467,  1068.  Rachis  flattened,  with  numer- 
ous patent  branches  from  the  edges  ;  much  twisted  and  con- 
torted ,  color  dark  green  ;  growing  in  lagoons  and  marshes. 
Greenland,  Mass.,  Wash.  Europe. 

18.  E.  INTESTINALIS   (L.)   Greville,    1830,  p.    179;    J.   G. 
Agardh,    1882,  p.   131,   PL  IV,  fig.  109;  Harvey,  1846-51,  PI. 
CUV  ;   P.  B.-A.,  No.  464;    UlvaJEnteromorpha  var.  intestinalis 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  205 

Farlow,  1881,  p.  43.  Frond  simple  or  having  at  the  base  a  few 
branches  similar  to  the  main  frond,  or  occasionally  a  few  pro- 
liferations above  ;  length  varying  from  a  few  centimeters  to  sev- 
eral meters  ;  diameter  from  1-5  cm.  ;  at  first  attached  by  a 
short,  cylindrical  stipe,  but  soon  detached  and  floating;  cylin- 
drical or  expanding  above,  more  or  less  inflated,  often  much 
crisped  and  contorted,  and  irregularly  and  strongly  constricted  ; 
cells  10-16  \t.  diam.,  in  no  regular  order;  thickness  of  membrane 
varying  from  50  ^  below  to  20  //,  above  ;  cells  in  cross  section 
from  12  to  30  p.. 

A  common  and  exceedingly  variable  species,  occurring 
throughout  our  range  except  on  the  southern  Atlantic  coast, 
where  E.  flexuosa  appears  to  take  its  place  ;  also  in  forma  tennis 
in  fresh  water.  There  are  many  intermediate  forms  that  con- 
nect it  with  E.  compressa,  but  in  its  typical  form  it  is  distin- 
guished by  the  internally  thickened  membrane,  and  by  the  in- 
testinal appearance,  which  is  indicated  by  both  its  generic  and 
its  specific  names.  It  is  especially  a  plant  of  quiet  waters, 
where  it  sometimes  attains  enormous  dimensions. 

Europe,  Brazil,  Japan. 

Among  the  many  forms  of  this  species  that  have  been  de- 
scribed, the  following  have  been  recognized  in  America  :  — 

Forma  CYLINDRACEA  J.  G.  Agardh,  1882,  p.  131  ;  P.  B.-A., 
No.  465.  Frond  long  and  slender,  of  uniform  diameter;  usu- 
ally floating  unattached.  Mass,  to  Conn.,  Alaska. 

Forma  CLAVATA  J.  G.  Agardh,  1882,  p.  131  ;  P.  B.-A.,  No. 
966.  Frond  attached,  clavate  from  a  filiform  stipe,  usually  more 
or  less  contorted.  N.  S.  to  Conn.;  Alaska  to  Cal.;  in  fresh 
water,  alt.  200  meters,  Cal. 

Forma  MAXIMA  J.  G.  Agardh,  1882,  p.  132;  P.  B.-A.,  No. 
1182.  Floating,  unattached;  inflated  and  bullate.  Me.  to  N. 
J.;  Alaska. 

Forma  TENUIS  Collins,  1903,  p.  23  ;  E.  intestinalis  Tilden, 
Amer.  Algae,  No.  125.  Frond  attached,  clavate  from  a  taper- 
ing stipe ;  membrane  thin  and  delicate,  not  thickened  within. 
In  size  and  shape  of  cells  and  habit  of  frond,  like  forma  davata 
of  salt  water ;  the  difference  in  the  character  of  the  membrane 
may  be  due  to  the  peculiar  station,  artesian  running  water.  So. 
Dakota.* 

*  This  may  be  the  same  as  E.  intestinalis  var.  crispa  Kutzing,  1849,  p. 
478 ;  but  the  description  of  the  latter  variety  is  insufficient  to  determine; 
"  Phycomate  majori  inflate  undulato-crispo.  In  aqua  dulci." 


206          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

19.  E.  LINZA  (L,.)  J.  G.  Agardh,  1882,  p.  134,  PL  IV,  figs. 
110-112;  P.  B.-A.,  Nos.  16,967;  Ulva  linza  Harvey,  1846-51, 
PL  XXXIX  ;  1858,  p.  59  ;  U.  enteromorpha  var.  lanceolata  Far- 
low,  1 88 1,  p.  43.  Frond  lanceolate  or  linear-lanceolate,  simple, 
1-5  dm.  long,  1-20  cm.  broad;  stipe  short,  hollow;  upper  part 
of  the  frond  flat,  the  membranes  grown  together  as  in  Ulva,  ex- 
cept at  the  edges,  where  they  remain  free.  Me.  to  W.  I.; 
Alaska  to  Cal.  Europe,  So.  America,  Tasmania. 

The  forms  of  this  species  are  divided  by  J.  G.  Agardh  under 
forma  crispata,  with  edges  much  crisped  and  folded,  and  forma 
lanceolata,  edges  even  or  plicate,  not  crisped.  In  one  or  the 
other  of  these  forms  the  species  seems  common  on  the  whole 
coast  of  the  U.  S.;  whether  extending  farther  south  is  not  cer- 
tain. It  grows  on  stones,  woodwork  and  other  algae,  usually 
in  places  seldom  or  never  left  bare  by  the  tide.  The  smaller 
forms  look  like  forms  of  E.  intestinalis,  but  in  the  latter  the 
frond,  though  often  collapsed,  is  tubular  throughout ;  in  E. 
linza  the  two  membranes  adhere,  except  at  the  edges,  where 
there  is  a  narrow  open  space,  around  which  the  cells  are 
arranged,  in  cross  section  nearly  in  a  circle. 

2.     ILEA  Fries,  1825,  p.  336. 

Frond  filamentous,  hollow,  gelatinous,  the  cells  mostly  in  twos 
and  fours,  enclosed  within  the  wall  of  the  mother  cell,  and 
arranged  in  distinct  longitudinal  series,  the  series  loosely  con- 
nected laterally. 

Only  one  species. 

I.  PULVESCENS  (Ag.)  J.  G.  Agardh,  1882,  p.  115  ;  P.  B.-A., 
No.  264;  Enteromorpha  aureola  Kiitzing,  1856,  p.  14,  PL  XL/, 
fig.  3.  Characters  of  the  genus.  Fig.  71.  Me.  to  N.  J.; 
Alaska.  Europe,  So.  Pacific. 

This  plant  grows  in  dense  tufts,  the  filaments  usually  5-20 
cm.  long,  the  diam.  being  seldom  over  2  mm.,  but  specimens 
have  been  found  one  meter  long,  2  cm.  diam.  The  fronds  are 
soft  and  gelatinous,  the  color  varying  from  dark  green  to  brown- 
ish or  yellow.  The  cells  have  a  distinctive  Gloeocapsa-like 
arrangement,  and  are  in  longitudinal  series  so  distinct  that  by 
pressure  on  the  cover  glass  they  readily  separate,  appearing 
like  free  filaments  of  one  or  two  cells  wide. 

It  grows  best  in  places  where  streams  of  fresh  water  empty 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  207 

into  the  sea,  occupying  the  space  between  high  and  low  water 
marks  ;  so  that  twice  each  day  its  medium  is  changed  from  sea 
water  to  quite  fresh  water,  and  back  again.  It  appears  to  be 
common  from  Maine  to  New  Jersey,  and  is  found  at  salt  springs 
at  Sussex,  New  Brunswick,  20  miles  from  the  sea. 
5.  MONOSTROMA  Thuret,  1854,  p.  13. 

Frond  at  first  a  closed  tube  or  sac,  which  later  opens  or  splits, 
forming  a  membranous  expansion,  of  a  single  layer  of  cells,  ex- 
cept at  the  base,  where  it  is  thickened,  and  may  consist  of  sev- 
eral layers  of  elongated  cells.  Two-  or  four-ciliate  zoospores 
and  biciliate  gametes  formed  in  any  of  the  cells  of  the  monostro- 
matic  part,  issuing  through  an  opening  at  the  surface  of  the 
frond. 

In  some  of  the  species  of  this  genus  the  saccate  form  has  not 
been  observed,  but  it  probably  occurs  in  all.  Its  persistence 
varies  much,  from  M.  latissimum,  in  which  the  frond  forms  a 
flat  expansion  when  only  two  or  three  mm.  high,  to  M.  groen- 
landicum,  in  which  the  greater  part  of  the  frond  continues  tubu- 
lar through  its  whole  life,  only  the  upper  part  opening  at  the 
time  of  the  formation  of  the  spores.  Some  of  the  smaller  species 
do  not  exceed  i  dm.  in  length;  others,  like  M.fuscum,  may 
reach  5  dm.  It  has  representatives  in  all  oceans,  and  several 
species  inhabit  by  preference  brackish  water ;  one  species  lives 
in  fresh  water  exclusively,  and  some  of  the  marine  and  brackish 
species  occasionally  occur  also  in  fresh  water. 

KEY  TO  THE  SPECIES  OF  MONOSTROMA. 

i.     Frond  always  tubular.  2. 

i.     Frond  tubular  only  in  an  early  stage  of  growth.  3. 

2.     Tube  filiform.  i.     M,  groenlandicum. 

2.     Tube  intestine-like,  collapsing. 

4.     M.  arcticum  var.  intestiniforme. 
3.     Frond  saccate  till  plant  is  well  developed  :  then  splitting  part  or  all 

of  the  way  to  the  base.  4- 

3.     Frond  saccate  only  in  the  early  stages  or  not  at  all.  5. 

4.     Segments  rather  broad,  irregularly  divided.        2.     M.  Grevillei. 

4.     Segments  narrowly  linear,  simple,  forked  or  palmate. 

3.    M.  Lactuca. 

5.     Frond  dark  to  dull  green,  not  adhering  to  paper,  n.       M,  fuscum. 
5.     Frond  light  or  bright  green,  adhering  generally  to  paper.  6. 

6.     Mature  frond  divided  into  distinct  segments.  7. 

6.     Frond  broadly  lanceolate  to  orbicular,  not  divided  into  segments. 

8. 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

7.     Segments  linear  or  lanceolate,  frond  about  6  /x  thick  above. 

5.     M.  pulchrum. 
7.     Segments  few,  broad  ;  frond  25-45  M  thick  ;  cells  close. 

4.     M,  arcticum, 
7.     Segments  obovate,  frond  18-36  n  thick  ;  cells  not  closely  set. 

7.     M.  crepidinum. 

8.     Frond  not  over  30 /a  thick,  except  near  the  base.  9. 

8.     Frond  40-50  //.  thick.  12. 

9.     Frond  not  usually  much  plicate.  10. 

9.     Frond  usually  much  plicate.  13. 

10.     Cells  arranged  in  distinct  groups  pf  4.        9.     M,  quaternarium. 

10.     Cells  not  in  distinct  groups  of  4.  n. 

ii.     Cells  in  longitudinal  and  transverse  series.  12.    M.  leptodermum. 

ii.     Cells  not  in  series.  8.     M.  latissimum. 

12.     Chromatophore  in  cross  section  not  over  9  /x  high. 

6.     M.  undulatum. 
12.     Chromatophore  in  cross  section  about  15  n  high. 

10.     M.  orbiculatum. 
13.     Frond  much  lobed,  margin  distinctly  thinner  than  base. 

10.     M.  orbiculatum  var.  varium. 
13.     Frond  not  much  lobed  ;  thickness  nearly  uniform. 

6.     M.  undulatum  var.  Farlowii. 

i.  M.  GROENLANDICUM  J.  G.  Agardh,  1882,  p.  107,  PI.  Ill, 
figs.  80-83;  P-  B.-A.,  No.  13.  Frond  filiform,  tubular,  cylin- 
drical, up  to  15  cm.  long,  from  a  very  slender  base  expanding 
to  i  mm.  diameter ;  apex  broken  only  at  exit  of  spores.  Cells 
in  the  lower  part  of  the  frond  loosely  arranged  in  twos  and 
fours,  roundish  angular ;  in  the  upper  part  more  evenly  distri- 
buted, more  or  less  closely  set.  In  cross  section  the  membrane 
is  25-35  fj-  thick ;  the  cells  radiately  elongate,  2-4  times  as  long 
as  broad ;  in  the  younger  parts  the  central  cavity  is  filled  with 
a  gelatinous  substance,  which  disappears  as  the  plant  becomes 
older.  Spores  or  gametes  formed  first  at  the  summit  of  the 
frond,  and  developing  successively  in  lower  cells.  Greenland 
to  Mass.;  Alaska. 

This  plant  has  no  external  resemblance  to  a  Monostroma,  and 
was  placed  in  this  genus  with  a  mark  of  doubt  by  both  Farlow 
and  Rosenvinge.  It  appears  like  a  slender,  unbranched  Entero- 
morpha,  but  seems,  however,  to  be  in  structure  more  nearly 
related  to  Monostroma.  It  occurs  from  April  to  June  in  New 
England  ;  in  July  at  Newfoundland  ;  and  from  May  to  August 
in  Greenland.  On  the  Atlantic  coast  it  grows  in  rather  dense 
tufts,  at  the  lower  limit  of  the  literal  zone,  in  company  with 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  209 

Spongonwrpha  arcta,  Bangia  fusco-purpurea,  Hormistia,  etc.  In 
all  specimens  from  the  Pacific  coast  that  have  been  examined,  the 
cells  are  decidedly  smaller  than  in  specimens  from  the  Atlantic ; 
8-10  fj.  diam.  in  the  former,  12-16  //.  diam.  in  the  latter,  seen 
superficially. 

2.  M.  GREVILLEI  (Thuret)  Wittrock,    1866,  p.   57,   PL   IV, 
fig.   14;  Farlow,   1881,  p.  41  ;  P.  B.-A.,   No.   15  ;    Ulva  Laduca 
Harvey,  1846-51,  PI.  CCXLIII ;   1858,  p.  60.     Frond  attached, 
at    first    saccate,    then    opening   at    the   top,    and    ultimately 
splitting  to  the  base  ;  soft  and  delicate,  pale  green  ;  membrane 
15-20  (*  thick,  cells  quadrate  with  rounded  angles,  closely  set  ; 
in  cross  section  horizontally  oval,   12-14  !"•  high-     Sporiferous 
cells  enlarged,  vertically  elongate  in  cross  section  ;  cell  wall  dis- 
solving after  emission  of  spores.     Greenland  to  N.  J.;  Alaska 
to  Cal.  Europe. 

The  saccate  form  is  plain  in  young  plants,  and  may  persist  for 
some  time  when  growing  in  still  water  ;  but  at  exposed  points 
the  frond  is  soon  torn  open,  and  in  mature  plants  all  trace  of 
the  original  shape  is  lost,  wherever  growing. 

An  early  spring  plant  except  in  Arctic  regions,  where  it  con- 
tinues till  August. 

Var.  VAHUI  (J.  Ag.)  Rosenvinge,  1893,  p.  949;  M.  Vahlii 
J.  G.  Agardh,  1882,  p.  109,  PI.  Ill,  figs.  84-89.  More  slender 
in  form,  often  cylindrical,  retaining  its  saccate  shape  longer, 
and  with  cells  arranged  in  more  or  less  distinct  longitudinal 
series.  An  early  spring  plant.  Greenland  to  Mass.;  Alaska. 

Var.  lubricum  (Kjellman)  nov.  comb.;  M.  lubricum  Kjellrnan, 
iSyya,  p.  48,  PI.  IV,  figs.  8  and  9.  Frond  up  to  15  cm.  long, 
pale  or  whitish  green,  delicate,  very  lubricous  and  flaccid,  of 
irregular  outline,  laciniate,  plicate,  margin  often  crisped  and 
lacerate;  frond  18-22  /A  thick;  cells  seen  superficially  circular 
or  rounded  angular,  often  in  twos  or  fours,  cell  wall  thick ;  in 
cross  section  horizontally  ovate  or  oblong,  4.5-8  p.  high.  Green- 
land, Alaska.  Northern  Europe. 

This  has  never  been  found  attached,  but  always  as  shapeless 
floating  fronds ;  with  our  imperfect  knowledge  of  it,  it  is  prob- 
able that  it  is  a  form  of  M.  Grevillei  in  which  the  cells  are  some- 
what shrunken,  the  membrane  much  gelatinized. 

3.  M.  LACTUCA  (Roth)  J.  Ag.,  1882,  p.  102,  PI.  Ill,  fig.  90; 
Areschoug,    Alg.    Scand.   Exsicc.,    No.    121;    P.    B.-A.,    No. 
1271.     Frond  at  first  an  elongate,  obconical  sac,  soon  splitting 
to  the  base  into  linear,  simple  or  forked  laciniae,  usually  with 


210          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

crisped  edges ;  membrane  20-25  /"•  thick  ;  cells  seen  superficially 
parenchymatously  united,  chromatophore  not  filling  the  cell  ; 
cells  angular,  often  arranged  in  twos,  threes  or  fours  ;  in  cross 
section  rounded,  horizontally  elongate,  15-18  p.  high.  Cell  walls 
persisting  after  emission  of  spores.  Mass.,  R.  I.,  Conn. 

Europe. 

A  spring  plant,  nearly  allied  to  M.  Grevillei,  but  quite  dis- 
tinct in  habit  and  texture.  It  has  a  thicker  membrane,  which 
is  also  firmer  and  less  lubricous.  M.  Grevillei  forms  at  first  a 
globular  or  obovate  sac,  splitting  into  broad  segments  of  indefi- 
nite shape  ;  M.  Lactuca  at  first  is  a  longer  sac,  and  divides  into 
long,  sublinear  laciniae,  often  with  a  tapering  stipe-like  base  ; 
when  these  laciniae  are  simple,  the  resemblance  to  Enteromorpka 
linza  is  striking  ;  when  they  fork,  which  is  often  the  case,  the 
resemblance  to  Ulva  fasciata  is  equally  marked  ;  there  are  some 
fronds  with  quite  distinct  palmate  division  of  the  laciniae. 

4.  M.  ARCTICUM  Wittrock,  1866,  p.  44,  PI.  II,  fig.  8 ;  P. 
B.-A.,  No.  910.  Frond  attached,  at  first  saccate,  soon  splitting 
into  a  few  broad  laciniae  ;  subradiately  plicate,  with  crisped 
margin  ;  pale  green,  becoming  yellowish  in  drying  ;  membrane 
25-45  M  thick  ;  cells  4-6  angled,  closely  set,  irregularly  placed  ; 
in  cross  section  either  vertically  or  horizontally  oval,  10-30  /j. 
high.  Greenland,  Alaska.  Northern  Europe. 

A  northern  species,  chiefly  distinguished  from  M.  Grevillci  by 
the  thicker  frond,  which  is  saccate  only  in  the  earliest  stages 
and  afterwards  appears  as  a  rather  broad  membrane,  not  split 
up  into  strips,  as  is  usual  in  M.  Grevillei.  M.  saccodeum  Kjell- 
man,  1883,  p.  296,  PI.  XXVIII,  figs,  i-io;  M.  cylindraceum 
Kjellinan,  1883,  p.  295,  PI.  XXX,  and  M.  angicava  Kjellman, 
1883,  p.  297,  PI.  XXIX,  seem  to  be  forms  of  M.  arcticum. 

Var.  intestiniforme  (Rosenv.)  nov.  comb.  ;  M.  Grevillei  var. 
intestiniforme  Rosenvinge,  1893,  p.  953,  fig.  52.  Frond  tubular, 
to  50  cm.  long  ;  membrane  25-50  /x.  thick  ;  cells  rounded,  closely 
set,  vertically  oval  in  cross  section,  15-20  yu,  high ;  usually  ar- 
ranged in  more  or  less  distinct  series  longitudinally.  Green- 
land. 

Resembles  in  habit  M.  Grevillei  var.  Vahlii,  but  in  thickness 
of  membrane  and  size  and  shape  of  cells  agrees  with  M.  arcticum  ; 
it  is  rather  persistently  tubular,  and  except  by  careful  ex- 
amination of  its  structure,  is  liable  to  be  mistaken  for  Entero- 
morpha  intestinalis . 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  211 

5.  M.  PULCHRUM   Farlovv,    1881,  p.  41  ;  P.  B.-A.,  No.  658. 
Frond  divided  into  linear  or  lanceolate  segments  with  slender 
base,  much  crisped  at  the  margin,  light  green,  membrane  about 
6  p.  thick  in  the  upper  part,  up  to   15  p.  near  the  base,  cells 
roundish,  rather  irregular  in  form. 

A  beautiful  species,  extremely  delicate,  adhering  so  closely  to 
paper  when  mounted  that  it  is  almost  impossible  to  detach  it  for 
examination.  It  occurs  on  rocky  shores,  usually  epiphytic  on 
other  algae,  from  April  to  June.  Newfoundland  to  R.  I. 

6.  M.  UNDULATUM  Wittrock,    1866,   p.   46,    PI.  Ill,   fig.  9. 
Frond  membranaceous,  soft  and  flaccid,  with  strongly  undulate 
margin ;    40-50   p.  thick ;    cells   angular,    closely   set,    showing 
somewhat  of   an  arrangement  in  twos,  .threes,  and  fours;    in 
cross  section  about  20  //.  high,  semicircular  or  oval ;  chromato- 
phore  not  occupying  the  full  height  of  the  cell  ;  not  over  10  //.  in 
the  middle.     Greenland.  Northern  Europe. 

The  typical  form  has  a  thicker  frond  than  any  other  species 
but  M.  fuscum,  which  is  not  likely  to  be  mistaken  for  it,  being 
amply  distinct  by  its  color  and  consistency. 

Var.  FARLOWII  Foslie,  1890,  p.  114;  P.  B.-A.,  No.  406. 
Frond  similar  to  the  type,  but  less  than  30  p.  thick.  Greenland 
to  Mass.  •  Norway. 

7.  M.  CREPIDINUM  Farlow,  1881,  p.  42;  P.  B.-A.,  No.  220. 
Frond  delicate,  light  green,  5-15  cm.  long,  flabellately  orbicu- 
late,  when  fully  developed  split  nearly  or  quite  to  the  base,  seg- 
ments obovate  ;  membrane  18-36,  rarely  45  /".thick  ;  cells  round- 
ish-angular, when  actively  dividing  forming  compact  groups  of 
2,  3,  or  4,  separated  by  rather  wide  spaces.     Mass,  to  N.  J. 

On  woodwork  between  tide  marks,  also  on  rocks  ;  it  is  usually 
in  rather  dense,  tufts,  which  have  a  rich  dark  green  color, 
though  the  individual  frond  is  light  green.  It  resembles  in 
habit  the  European  M.  Wittrockii,  but  has  a  thicker  frond,  with 
cells  more  elongate  horizontally  in  cross  section.  M.  Wittrockii 
is  more  membranaceous  in  texture,  not  adhering  well  to  paper. 

8.  M.  LATISSIMUM  (Kiitz.)  Wittrock,   1866,  p.  33,  PI.  I,  fig. 
4;  P.  B.-A.,  Nos.  14,  1122.     Frond  at  first  attached,  afterwards 
floating ;  thin  and  soft,  glossy,  of  irregular  shape,  more  or  less 
plicate  near  the  even  or  undulate  margin  ;  membrane  20-25  P- 
thick,  cells  4-6-cornered  or  roundish,  closely  set,  without  order 
or  more  or  less  distinctly  in  twos,  threes,  and  fours ;  in  cross 
section  vertically  oval  or  nearly  circular,  14-18  n  high.     Me.  to 
Fla.;  Alaska  to  Washington.          Europe,  Africa,  New  Zealand. 


212        TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Apparently  not  uncommon  in  quiet  waters,  especially  in 
ditches  in  marshes,  where  the  water  is  sometimes  brackish 
rather  than  salt.  At  first  it  is  attached  to  various  objects,  but 
soon  becomes  loosened  and  floats  freely,  sometimes  in  such 
abundance  as  to  quite  fill  a  ditch  from  bottom  to  surface.  It 
appears  in  spring,  and  continues,  chiefly  in  the  floating  state, 
through  the  summer.  The  arrangement  of  cells  varies  in  plants 
from  the  same  locality,  and  even  in  different  parts  of  the  same 
frond ;  indeed,  the  shape  of  the  cells,  whether  seen  from  above 
or  in  cross  section,  is  liable  to  vary  in  any  species  of  Monostroma, 
or  in  different  stages  of  growth  of  the  individual. 

9.  M.  QUATERNARIUM  (Ku'tz.)  Dcsmazieres,  Plantes  Crypt, 
de  France,  Troiseme  Serie,  No.  603,   1859;  Wittrock,  1866,  p. 
37,   PI.   I,  fig.  5;   P.  B.-A.,    No.    567;    Ulva  quaternaries  Kiitz- 
ing,  1856,  p.  6,  PI.  XIII,  fig.  2.     Frond  at  first  attached,  soon 
becoming  free,  soft  and  delicate,  irregularly  lobed  and  folded, 
20-23 /u,  thick  ;  cells  rounded,  when  actively  dividing  set  closely 
in  threes  and  fours  within  the  mother  cell  wall ;  in  cross  section 
semicircular  or  oval,  15-17  p  high.     In  brackish  or  fresh  water, 
Washington  to  Cal.  ;  various  fresh  water  localities  throughout 
the  western  U.  S.  .  Europe. 

10.  M.  ORBICULATUM  Thuret,  1854,  p.  388;  Wittrock,  1866, 
p.  39,  PL  II,  fig.  6;   Alg.   Am.    Bor.,   No.    173.     Frond  mem- 
branaceous,  attached  by  fibrils,  or  later  free  ;  soft  and  flaccid, 
sub-orbicular  or  irregular  in  outline,  often  radially  plicate,  with 
undulate  margin,  30-40  /u.  thick  ;  cells  angular,  varying  much  in 
size  and  arrangement,  often  irregularly  elongate,  closely  set, 
but  with  chromatophore  not  occupying  the  whole  cell ;  in  cross 
section   vertically  oval,  25-30  p.  high.     In  fresh  and  brackish 
water.     Bermuda,  Cal.  Europe. 

Like  other  species,  this  varies  much  in  color,  the  Bermuda 
plant  being  a  full  green,  the  California  plant  quite  pale.  In  the 
Bermuda  specimens  the  frond  is  somewhat  thinner  than  the 
type,  and  the  radical  fibrils  are  strongly  developed. 

Var.  VARIUM  Collins,  19093,  p.  26.  Frond  very  much  lobed 
and  plicate,  forming  a  rosette-like  expansion,  attached  at  the 
center  ;  frond  50-60  /A  thick  in  the  older  part,  diminishing  to  16 
^  at  the  margin.  On  muddy  shore  near  low  water  mark. 
So.  Mass. 

The  much  divided  and  very  much  folded  frond  is  quite  differ- 
ent in  appearance  from  the  typical  M.  orbiculatum,  but  no  differ- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  213 

ence  can  be  seen  in  the  form  and  dimensions  of  the  cells,  except 
that  the  membrane  is  thicker  in  the  older  parts  and  thinner  in 
the  younger  in  var.  variuin,  than  in  the  type,  in  which  the  frond 
is  of  nearly  uniform  thickness. 

11.  M.  FUSCUM  (Post,  and  Rupr.)  Wittrock,  1866,  p.  53,  PI. 
IV,  fig.  13.     Frond  membranaceous,  at  first  tubular,  soon  split- 
ting, dull  green,  more  or  less  lobed  but  not  divided  to  the  base  ; 
membrane  20-35  //.  thick  ;  cells  4-6-angled,  very  closely  set ;  in 
cross   section    quadrate,    with   only  slightly  rounded    corners ; 
occupying  nearly  the  entire  thickness  of  the  frond.     Greenland, 
Alaska.  Northern  Europe. 

Under  this  species  are  included  two  forms,  which,  with  the 
type,  pass  into  each  other  with  no  dividing  line,  while  they  are 
sharply  marked  off  from  all  other  species  of  the  genus  in  nearly 
every  respect.  The  very  young  plant  is  in  the  form  of  a  closed 
tube,  which  soon  splits  down  one  side,  and  spreads  out  to  form 
a  flat  membrane  ;  not  splitting  into  several  segments,  as  in  the 
Grevillei  group.  Compared  with  other  species  of  Monostroma, 
the  fuscum  forms  are  thick  and  coarse,  blackish  when  dried, 
staining  the  paper  on  which  they  are  mounted,  and  not  adher- 
ing well  to  it. 

Forma  BLYTTII  (Wittr.)  Collins,  1903,  p.  12  ;  M.  Blyttii  Witt- 
rock,  1866,  p.  49,  PI.  Ill,  fig.  ii  ;  Farlow,  1881,  p.  41  ;  M.  fus- 
cum, P.  B.-A.,  No.  715.  Frond  deep  green,  blackish  in  drying, 
60-70  [i.  thick  ;  cells  "  palisade-form  "  in  cross  section.  Fig.  72. 
Greenland  to  R.  I.  ;  Vancouver  Island,  Washington. 

A  plant  of  late  autumn  and  winter  in  New  England,  in  tide 
pools  and  also  on  pebbles  in  the  sublitoral  zone ;  great  quanti- 
ties are  sometimes  washed  ashore  by  storms,  the  stones  on 
which  they  grew  remaining  attached  to  them. 

Forma  SPLENDENS  (Wittr.)  Collins,  1903,  p.  12;  P.  B.-A., 
No.  911  ;  M.  splendens  Wittrock,  1866,  p.  50,  PI.  Ill,  fig.  12. 
Frond  deep  green,  glossy,  50-55  fi  thick,  more  deeply  parted 
than  in  the  other  forms  ;  cells  similar  to  those  of  forma  Blyttii, 
or  more  rounded.  Alaska  to  Vancouver  I.  Northern  Asia. 

12.  M.  LEPTODERMUM  Kjellman,  1877,  p.  52,  PI.  I,  figs.  23  and 
24;   P.  B.-A.,  No.  1272;  M.  zostericolum  Tilden,  Amer.  Algae, 
No.  388.     Frond  cuneate-obovate  9r  divided  into  segments  of 
that  form  ;    cells  squarish,  in  distinct  series,   longitudinal  and 
transverse  ;  the  former  often  radiate,  the  latter  concentric  ;  mar- 


214  TUFTS  COLLEGE;  STUDIES,  VOL.  II,  No.  3 

gin  more  or  less  undulate;  membrane  7-10  ju.  thick,  cells  quad- 
rate in  cross  section,  5-8  yu,  high.      Greenland  (?),  Mass.,  Wash. 

Arctic  Sea. 

This  species  has  the  most  delicate  frond  of  all  the  genus, 
except  M.pidchrum,  and  grows  in  spring  below  low  water  mark 
or  in  pools.  It  was  founded  by  Kjellman  on  specimens  found 
unattached,  without  basal  part  ;  Rosenvinge,  1893,  p.  944, 
identifies  with  it  a  plant  from  Greenland,  with  a  filiform,  tubu- 
lar stipe  of  varying  length.  No  such  stipe  has  been  seen  in  the 
specimens  from  Massachusetts  and  Washington  ;  hundreds  of 
specimens  of  all  stages  of  growth  have  been  examined,  without 
finding  any  indications  of  a  stipe.  The  structure  of  our  plant 
agrees  with  Kjellman's  description  and  figures,  and  his  name  is 
here  retained  ;  it  may  be  that  the  Greenland  plant  is  distinct 
from  that  of  northern  Europe.* 

4.     ULVA  Linnaeus,  1753,  p.  1163. 

Frond  membranaceous,  flat,  consisting  of  two  layers  of  cells, 
in  any  of  which,  except  those  in  the  thickened  base,  zoospores 
or  gametes  may  be  formed,  issuing  through  an  opening  in  the 
surface  of  the  frond.  Marine. 

KEY  TO  THE  SPECIES  OF  ULVA. 

i.     Frond  divided  into  distinct  segments.  3.     U.fasciata. 

i.     Frond  entire  or  irregularly  lobed  or  laciniate.  2. 

2.     Frond  minute,  triangular  or  reniform,  with  distinct  stipe. 

2.     U.  californica. 
2.     Frond  ample,  at  first  lanceolate,  later  of  no  definite  outline. 

i.     U.  Lactuca. 

i.  U.  LACTUCA  Linnaeus,  1753,  p.  1163;  Thuret  and  Bor- 
net,  1878,  p.  5,  Pis.  II,  III ;  U.  Lactuca  var.  Lactuca  Farlow, 
1 88 1,  p.  43.  Frond  very  variable  in  shape,  at  first  attached  and 
generally  of  a  lanceolate  or  ovate-lanceolate  form  ;  later  of  irreg- 
ular shape,  and  often  detached  and  floating.  The  cells  usually 
vertically  elongate  in  cross  section ;  seen  from  the  surface 
irregularly  angular,  cfesely  set ;  thickness  of  the  frond  very 
variable.  Fig.  75. 

*There  have  been  several  reports  of  M.  thermalis  from  interior  points 
of  the  United  States,  and  in  some  cases  the  determination  was  confirmed 
by  J.  G.  Agardh.  But  the  latter,  1882,  p.  no,  expresses  considerable 
doubt  as  to  whether  what  he  understands  as  M.  thermalis,  is  the  same  as 
the  Ulva  thermalis  of  Meneghini,  1837,  p.  21.  All  the  American  speci- 
examined,  including  several  in  Herb.  Farlow,  prove  to  be  species  of 
Enteromorpha. 


THE;  GREEN  ALGAE  OF  NORTH  AMERICA  215 

A  very  common  plant  over  the  whole  world,  and  extremely 
variable  in  form,  thickness  and  color.  Two  fairly  marked 
types  can  be  distinguished  in  the  species  as  found  with  us  on 
both  Atlantic  and  Pacific  coasts,  connected  by  innumerable 
forms. 

Var.  RIGIDA  (Ag.)  Le  Jolis,  1863,  p.  38;  Farlow,  1881,  p. 
42  ;  P.  B.-A.,  No.  407.  Frond  at  first  lanceolate  or  ovate- 
lanceolate,  firm  and  stiff,  with  a  distinct  stipe  ;  later  somewhat 
irregularly  divided,  and  often  with  numerous  perforations  of 
various  sizes  ;  cells  vertically  elongate  in  cross  section. 

This  is  a  common  form  of  exposed  shores,  but  occurs  also 
sometimes  in  quieter  waters.  In  its  earlier  stages  it  is  dis- 
tinctly lanceolate  in  outline,  but  this  form  is  afterwards  lost  by 
irregular  growth.  It  is  firm  in  texture,  the  color  deepening  as 
the  plant  grows  older,  finally  becoming  brownish  or  blackish  ; 
the  cells  have  their  greatest  length  at  right  angles  to  the  surface 
of  the  frond,  being  sometimes  three  times  as  long  as  wide. 

Var.  LATISSIMA  (L.)  DC.,  1.805,  p.  9 ;  P.  B.-A.,  No.  LXXVI. 
Frond  irregular  in  outline,  soon  becoming  detached  and  parsing 
most  of  its  life  in  a  floating  condition  ;  thinner  than  var.  ngida, 
lighter  colored,  and  with  cells  nearer  square  in  cross  section. 

This  is  a  common'  form  of  creeks  and  lagoons,  where  it  forms 
floating  sheets,  often  of  several  square  meters  in  extent. 

Var.  MESENTERIFORMIS  (Roth)  Collins,  1900,  p.  45.  Frond 
much  contorted  and  bullate,  forming  crumpled  masses,  lying 
loose  on  the  bottom. 

This  form  is  strikingly  distinct  in  appearance,  forming  much 
crisped  and  wrinkled  masses,  usually  of  a  dark  green  color, 
lying  on  the  bottom  in  creeks  and  quiet  bays.  It  is  so  twisted 
and  grown  together  that  only  by  tearing  can  even  a  small  piece 
of  it  be  spread  out  flat.  In  cross  section  the  cells  are  nearer 
square  than  those  of  the  type.  It  is  common  in  marshy  pools 
near  Bridgeport,  Conn.,  and  will  probably  be  found  in  similar 
places.  Known  elsewhere  only  in  the  Baltic. 

2.  U.  CALIFORNICA  Wille,  P.  B.-A.,  No.  6n.  Frond  1.5 
to  2  cm.  long,  up  to  1.5  cm.  wide,  triangular  or  reniform  with 
wavy  edge,  sometimes  with  proliferations  of  a  few  cells  each ; 
passing  quickly  into  a  flattened,  tapering  stipe.  The  cells  of 
the  stipe,  which  on  the  inner  side  form  rhizoidal  prolongations, 
are  in  cross  section  about  quadrate  ;  the  cells  in  the  upper  part 


2i6          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

of  the  frond  are  rather  irregularly  polygonal  with  rounded  cor- 
ners ;  no  noticeable  arrangement  in  longitudinal  series ;  frond 
about  30  /A  thick. 

A  species  with  minute  fronds,  with  more  definite  outline  than 
is  usual  in  species  of  this  genus.  It  is  known  only  from  Cali- 
fornia, where  it  forms  a  rather  dense  coating  on  rocks  near  high 
water  mark.  Hardly  enough  is  known  of  this  plant  to  decide 
whether  its  position  is  permanently  assured. 

3.  JJ.  FASCIATA  Delile,  1813,  p.  153,  PI.  LVIII,  fig.  5  ; 
Harvey,  1858,  p.  58;  P.  B.-A.,  No.  221.  Frond  divided  into 
more  or  less  linear  segments,  margin  smooth  or  undulate  ;  in 
cross  section  the  two  layers  of  cells  separate  somewhat  at  the 
margin,  which  is  rounded,  with  a  small,  open  space  between 
the  rows.  Fla.,  W.  I.,  Cal.  Warm  waters  all  over  the  world. 

The  structure  of  the  frond  is  similar  to  that  of  U.  Lactuca,  ex- 
cept the  margin,  which  resembles  Enteromorpha  linza  ;  but  the 
shape  of  the  frond,  with  definite  divisions,  is  quite  distinct  in  the 
typical  form.  On  the  Californian  coast,  however,  it  is  hard  to 
draw*  the  line  between  this  and  U.  Lactuca,  either  from  the 
shape  of  the  frond  or  from  its  structure.  Even  in  the  typical 
form  there  is  much  diversity  as  to  the  divisions  of  the  frond  ; 
they  may  be  dichotomous  or  apparently  lateral ;  their  width 
may  vary  from  5  mm.  to  5  cm.  ;  and  the  frond  may  reach  a 
length  of  a  meter ;  the  margin  may  be  smooth  and  even,  or 
much  crisped  and  undulate  ;  in  this  last  it  corresponds  to  forms 
of  Enteromorpha  linza.  Four  forms  have  been  distinguished 
on  the  Pacific  coast,  passing  into  each  other  more  or  less. 

Forma  TAENIATA  Setchell,  P.  B.-A.,  No.  862.  Lobes  slen- 
der and  elongated,  crisped  and  ruffled  ;  prominent  teeth  on  the 
margins  near  the  base  of  the  frond. 

Forma  CAESPITOSA  Setchell,  P.  B.-A.,  No.  809.  Divisions 
numerous,  irregular;  fronds  intricately  entangled,  forming  a 
dense  coating  on  the  rocks. 

Forma  LOBATA  Setchell,  P.  B.-A.,  No.  863.  Lobes  short 
and  broad,  seldom  crisped  or  ruffled. 

Forma  EXPANSA  Setchell,  P.  B.-A.,  No.  LXXVII.  Frond 
ample,  of  generally  orbicular  outline,  lobes  broad  or  narrow, 
more  or  less  sinuous,  margin  much  ruffled  ;  frond  60-70/4  thick,, 
cells  somewhat  elongate  in  cross  sjection. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  217 

PROTODERMA  Kiitzing,  1843,  p.  295. 

Frond  a  minute  disk,  closely  attached  to  the  substratum, 
formed  originally  of  radiating,  branching  filaments,  which,  ex- 
cept at  the  margin,  are  united  to  a  sub-parenchymatous  layer  of 
one  or  more  cells  in  thickness ;  cells  with  parietal  disk-shaped 
chromatophore  and  one  pyrenoid  ;  asexual  reproduction  by 
aplanospores  and  by  biciliate  zoospores  with  red  stigma. 

The  proper  position  of  this  genus  is  quite  uncertain ;  West, 
1904,  places  it  in  the  Pleurococcaceae  ;  Oltmans,  1904,  ignores 
it ;  it  must  be  placed  somewhere,  and  in  the  Ulvaceae  is  as 
good  a  place  as  any.  There  is  no  doubt  that  immature  organ- 
isms of  many  kinds  have  passed  under  the  name  of  P.  viride, 
but  P.  marinum  is  more  distinct. 

KEY  TO  THE  SPECIES  OF  PROTODERMA. 

I.     Fresh  water.  i.     P,  viride. 

i.     Marine.  2.     P.  marinum. 

i.  P.  VIRIDE  Kiitzing,  1843,  p.  295  ;  1856,  p.  6,  PI.  XI,  fig.  i. 
Frond  pale  green,  at  first  circular,  later  more  or  less  irregular; 
filaments  parenchymatously  united  in  the  interior  of  the  disk, 
free  at  the  margin  ;  cells  in  the  young  frond  with  thin  wall, 
cylindric  to  cuneate,  3-6  ft  wide,  usually  2-3  times  as  long ; 
in  middle  of  adult  frond  6-8,  or  even  12  ft  wide,  1-2  times  as 
long,  spherical,  ovoid,  or  ellipsoid,  with  thick  wall ;  zoospores 
globose  to  ovoid,  3-3.5  ft  diam.  ;  aplanospores  globose  to  ellip- 
soid, 2-3  ft  diam.  Fig.  73.  On  wood  and  stones  in  ponds. 
Mass.,  Barbados.  Europe. 

"  2.  P.  MARINUM  Reinke,  1889,  p.  81  ;  P.  B.-A.,  No.  LIII. 
Forming  thin  coatings  of  irregular  form,  composed  of  angular, 
parenchymatously  united  cells,  6-12  // .wide,  irregularly  placed, 
except  at  the  margin,  there  in  rather  indistinct  radiating  series. 
Me.  to  Conn.  Europe. 

Common  as  a  thin  green  film  on  pebbles  in  pools  and  at  low 
water  mark,  along  the  New  England  coast ;  probably  elsewhere. 

Family  3.     PRASIOLACEAE. 

Filamentous  or  membranaceous ;  cells  with  star-shape  chro- 
matophore and  one  pyrenoid  ;  asexual  reproduction  by  segment- 
ation of  the  frond,  by  akinetes  and  by  aplanospores ;  sexual 
reproduction  unknown.  Fresh  water  or  marine. 

KEY  TO  THE  GENERA  OF  PRASIOLACEAE. 

i.     Frond  normally  of  a  single  series  of  cells,  occasionally  expanding 
laterally  to  two  or  a  few  series.  i.     SCHIZOGONIUM. 


2i8  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

i.     Frond  at  first  of  a  single  series  of  cells,  soon  becoming  a  membrane. 

2.     PRASIOLA. 

i.     Frond  at  first  of  a  single  series  of  cells,  soon  becoming  a  terete  multi- 
cellular  filament.  3.     GAYELLA. 

i.     SCHIZOGONIUM  Kiitzing,  1843,  p.  245. 

Frond  normally  a  filament  of  a  single  series  of  cells,  but  at 
times  dividing  longitudinally,  so  as  to  form  ribbon-shaped 
fronds,  two  or  a  few  cells  wide  ;  cells  usually  shorter  than 
their  diameter,  with  central  stellate  chromatophore  and  one 
pyrenoid  ;  asexual  reproduction  by  akinetes  and  aplanospores. 

Usually  terrestrial  algae,  normally  filamentous,  occasionally 
dividing  longitudinally,  but  not  forming  distinctly  foliaceous 
expansions.  Gay,  1891,  gives  a  broader  extension  to  the  genus, 
adding  6".  cri spurn,  which  appears  here  as  Prasiola  crispa.  This 
species  produces  filamentous  fronds  which  may  or  may  not 
develope  into  membranes  ;  it  connects  the  two  genera,  and  it  is 
not  easy  to  decide  under  which  to  include  it. 

KEY  TO  THE  SPECIES  OF  SCHIZOGONIUM. 
i.     Uniseriate  filaments  cylindrical  ;  multiseriate  not  uncommon. 

i.     5.  murale. 

i.     Uniseriate  filaments    moniliform   or   crenulate ;    longitudinal   cell- 
division  in  a  single  cell  or  in  a  few  successive  cells. 

2.     5.  crenulatum. 

1.  S.  MURALE  Kiitzing,    1843,   p.   246;  Gay,    1891,   p.  87,  PI. 
XIII,  figs.  122-125.     Forming  a  soft,  tomentose  stratum,  bright 
or  dull  green ;  filaments  flexuous,  simple  or  rarely  with  short, 
few-celled  branches;  cells  usually  10-14/11  diam.,  occasionally  a 
little  more  or  less ;  often   biseriate ;    rarely  pluri-seriate.     On 
moist  earth,  rocks,  trees,  etc.     N.  H.,  Alaska.  Europe. 

Var.  ALPINUM  Farlow,  P.  B.-A.,  No.  70.  Submerged; 
forming  long,  loose,  floating  tufts  in  mountain  brooks.  N.  H. 

2.  S.  CRENULATUM  (Kiitz.)  Gay,    1888,  p.  72  ;    1891,  p.  88, 
PI.   XIII,   fig.    131.     Forming  a  thin    stratum,  bright  or   dull 
green  ;  filaments  more  or  less  moniliform  or  crenulate,  rather 
stiff,  entangled,  11-14  A1  diam.,  occasionally  one  or  a  few  cells 
duplicated;  cells  about  as  long  as  broad,  more  or  less  swollen 
at  the  middle,   walls  between  the  cells  quite  thick.      Fig.   76. 
On  moist  wood,  etc.      N.  H.,  Mass.  Europe. 

2.     PRASIOLA  (Ag.)  Meneghini,  1838,  p.  36. 
Fronds  membranaceous,  monostromatic,  attached  by  short  fili- 
form prolongations,  by  the  edge  of  the  membrane,  or  by  a  thick- 


THE  GREEN  ALG'AE  OF  NORTH  AMERICA  219 

ened  stipe  ;  cells  with  stellate  chromatophore  and  one  pyrenoid, 
dividing  to  form  groups  of  fours,  these  groups  forming  similar 
larger  groups,  the  spaces  between  the  groups  of  various  orders 
constituting  narrower  or  wider  spaces,  running  in  definite  direc- 
tions through  the  frond.  Asexual  reproduction,  ist,  by  the 
breaking  off  of  small  portions  of  the  frond,  which  attach  them- 
selves and  grow  independently  ;  2d,  by  akinetes  formed  from 
individual  cells  assuming  thick  walls :  these  akinetes  may 
develop  either  directly  into  a  filament  or  membrane,  or  indi- 
rectly by  aplanospores,  several  in  each  akinete  ;  3d,  by  aplano- 
spores,  formed  4-8  in  a  cell,  by  walls  in  2  or  3  directions  ;  sexual 
reproduction  unknown. 

The  species  of  this  genus  resemble  small  forms  of  Ul-va  or 
Monostroma  ;  most  of  them  are  so  minute  as  to  be  barely  notice- 
able, but  some  may  reach  a  length  of  10  cm.  Some  species 
grow  in  cold  mountain  streams,  but  most  of  them  are  found  in 
moist  places,  not  immersed  ;  some  inhabit  by  preference  quite 
uncleanly  stations ;  a  few  species  are  marine.  While  there 
have  been  reports  of  the  production  of  zoospores,  it  is  now  gen- 
erally supposed  that  these  reports  were  based  on  misapprehen- 
sions, and  that  the  reproduction  is  asexual  and  non-motile.  In 
the  character  of  the  frond,  and  in  the  formation  of  spores,  there 
are  quite  interesting  similiarities  between  Prasiola  and  Porphyra. 

KEY  TO  THE  SPECIES  OF  PRASIOLA. 

i.     Marine.  4-     /*.  borealis. 

i.     Fresh  water  or  terrestrial.  2. 

2.     Frond  with  long,  stipe-like  base.  3. 

2.     Stipe  short  or  wanting.  4. 

3.     Frond  near  base  of  a  single  series  of  cells.  i.     P.  calophylla. 

3.     Frond  always  of  several  series  of  cells.  2.     P.  fluviatilis. 

4.     Terrestrial.  5-     P-  crispa. 

4.     In  cold  mountain  streams.  3.     P.  mexicana. 

i.  P.  CALOPHYU.A  (Spreng.)  Meneghini,  1838,  p.  36;  Jes- 
sen,  1848,  p.  14,  PI.  I,  figs.  1-3;  P.  B.-A.,  No.  1273.  Fronds 
linear  to  narrowly  cuneate,  with  truncate  apex,  many  from 
the  same  holdfast,  seldom  over  i  cm.  long,  i  mm.  wide ;  cells 
near  the  base  in  a  single  series,  about  10  p.  long  by  3-5  n  broad  ; 
farther  up  in  two  rows,  the  number  increasing  towards  the  upper 
part  of  the  frond  or  as  the  frond  grows  older ;  the  series  of  cells 
and  the  intercellular  lines  nearly  parallel  throughout ;  cells  near 
the  apex  of  the  frond  about  3-5  t*.  square  ;  thickness  of  frond 
about  15  P.  ;  cells  8-10  //.  high  in  cross  section.  Wash.,  Cal. 

Europe. 


220  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

The  minute  linear  fronds  with  filiform  stipe  and  truncate 
apex,  distinguish  this  species  from  others  of  the  genus. 

2.  P.   FLUVIATILIS    (Sommerf.)  Areschoug   in   Lagerstedt, 
1869,  p.   28;  Wittr.   and  Nordst.,  Alg.  Exsicc.,  No.  1234;  P, 
Sauteri,  Jessen,    1848,  p.    15,  PI.  I,  figs.  4-9.     Fronds  cuneate- 
lanceolate  to  obovate,  to  10  cm.  high,  2  cm.  wide,  apex  obtuse, 
not  truncate  ;  cells  near  the  base  in  a  few  series,  above  more 
numerous ;  series  of  cells  and  intercellular  spaces  parallel  be- 
low, more  areolate  in  the  upper  part ;  cells  4-6  p.  wide ;  frond 
I3-19  P-  thick,  cells  8-13  /u,  in  cross  section.     Greenland,  Alaska. 

Europe. 

A  plant  of  cold  mountain  streams,  in  general  shape  somewhat 
like  P.  calophylla,  but  larger,  with  rounded  apex,  and  without 
monosiphonous  stipe  except  at  very  early  stages. 

3.  P.  MEXICANA  J.  G.  Agardh,  1847,  p.  6  ;  Jessen,  1848,  p. 
19,  PI.  I,  figs.  17-20  ;  P.  B.-A.,  No.  1186.     Frond  up  to  10  cm. 
long  and  wide,  of  more  or  less  rounded  outline,  attached  by  a 
short,   thickened  stipe;   cells  6- 1 6  /A  diam.,  rather  closely  set  ; 
asexual  reproduction   by  division   of   frond,  by  akinetes  more 
rounded   than  the  vegetative   cells,  and   with   slightly  thicker 
wall  ;  and  by  aplanospores  formed  8-16  in  a  cell,  in  the  upper 
marginal  portion  of  the  frond,  from  subglobose  to  oblong,  6-8  p. 
wide,  up  to  14  /A  long.     In  cold  mountain  streams,  sometimes  at 
very  high  altitudes.     Wyo.,  Oregon,  Colo.,  Mexico. 

So.  America. 

In  appearance  quite  like  a  small  Ulva  ;  the  areolate  character 
is  not  so  conspicuous  as  in  some  other  species  ;  at  the  formation 
of  the  aplanospores  the  margin  for  a  greater  or  less  depth  be- 
comes softer  and  of  lighter  color,  very  much  in  the  same  way  as 
on  the  formation  of  the  antheridia  in  Porphyra. 

4.  P.  BOREALIS  Reed,  1902,  p.  160,  PI.  XV.     Fronds  cune- 
ate  to  obovate,  stipitate  or  sessile,  margin  crenulate,  crisped  or 
entire,  soft  membranaceous,  33-45   p-  thick,   5-10  mm.  high,  in 
tufts  of  several  from  one  holdfast ;  cells  in  distinct  tetrads,  areo- 
lar  arrangement  manifest  ;  cells  4-9  p.  diam.,  seen  superficially  ; 
in   cross  section  oblong   or  palisade-form,    11-14  P-   high-     On 
rocks  near  high  water  mark.     Alaska. 

The  fronds  of  this  species  are  very  generally  infested  with  a 
fungus,  Guignardia  Alaskana  Reed  ;  it  has  its  counterpart  in 
antarctic  regions  in  Prasiola  tesselata  Kiitz.,  infested  by  Gnig- 
nardia  Prasiolae  (Winter)  Reed. 

5.  P.    CRISPA    (Lightf.)    Meneghini,    1838,   p.   36;    Jessen, 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  221 

1848,  p.  18,  PI.  I,  figs.  10-16;  Wolle,  1887,  p.  106,  PI.  XCI, 
figs.  25-27;  P.  B.-A.,  Nos.  1069,  1184.  Frond  of  indefinite 
form,  rounded,  lacerate,  or  plicate,  without  stipe,  attached  to 
substratum  by  the  edge  of  the  frond  or  by  fine  fibrils ;  usually 
in  dense  masses  ;  fronds  sometimes  as  much  as  10  cm.  high  or 
wide,  but  usually  much  smaller  ;  generally  13-16  /u.  thick  ;  cells 
squarish  or  rectangular,  8-13  /u.  diam.,  in  cross  section  square  or 
slightly  higher  than  wide.  Fig.  77.  In  moist  and  especially  in 
unclean  places.  Greenland,  Newfoundland,  Alaska,  Cal. 

Europe. 

The  description  given  above  is  of  the  normal  adult  frond  ; 
along  with  this  are  generally  found  very  narrow  forms,  only  two 
or  three  cells  wide,  and  also  forms  of  a  single  series  of  cells  ; 
the  latter  agreeing  in  every  way  with  what  has  been  known  as 
Hormidium  parietinum  or  H.  murale ;  these  have  been  distri- 
buted as  P.  B.-A.,  Nos.  969,  1274;  but  every  gradation  can  be 
found  between  these  and  the  typical  Prasiola  fronds,  and  there 
is  little  doubt  that  under  certain  conditions  or  in  certain  stages 
the  Prasiola  develops  the  Hormidium  forms.  The  areolate 
structure  is  not  so  clear  in  P.  crispa  as  in  some  other  species, 
but  it  shows  distinctly  enough  in  the  younger  plants,  becoming 
less  distinct  as  the  plant  grows  older.* 

3.     GAYELLA  Rosenvinge,  1893,  p.  936. 

Frond  filiform,  simple  or  very  slightly  branched,  at  first  of  a 
single  series  of  cells,  later  dividing  longitudinally  into  many 
series,  but  always  remaining  filiform,  not  flat ;  cell  structure  as 
in  Prasiola.  Marine. 

G.  POLYRHIZA  Rosenvinge,  1893.  p.  937,  figs.  45  and  46; 
P.  B.-A.,  No.  914.  Frond  at  first  a  simple  filament  of  a  single 
series  of  disk-shaped'  cells,  10-12  //.  diam.,  attached  to  the  sub- 
stratum by  a  rhizoidal  projection  from  the  lower  cell ;  later 
attached  at  various  parts  of  the  filament  by  rhizoidal  growths, 
one  or  two  from  a  cell ;  increasing  in  diameter  by  growth  and 
division  of  cells,  up  to  70  n  diam.;  terete  or  somewhat  irregular 
in  surface,  but  not  flattened  ;  cells  with  parietal  chromatophore 
and  one  pyrenoid  ;  in  the  mature  plant  showing  superficially  an 
arrangement  in  longitudinal  and  transverse  Hues ;  in  cross  sec- 
tion an  arrangement  by  2-4-8-16,  etc.,  in  somewhat  Gloeocapsa- 
like  form  ;  asexual  reproduction  by  aplanospores,  arranged  in 

*P.  Gardneri  Collins,  P.  B.-A.,  No.  1185.  there  placed  with  some  doubt 
in  this  genus,  seems  on  further  study  to  belong  rather  to  the  blue-green 
algae. 


222  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

longitudinal  and  horizontal  series.     Figs.  78,  79.     Greenland, 
Alaska. 

Borgesen,  1902,  p.  482,  includes  Gayella  in  Prasiola  crispa  as 
subspecies  maiina.  It  is  certainly  hard  to  draw  the  line  be- 
tween Prasiola,  Schizogonium  and  Gayella  ;  but  the  habit  of  Gay- 
ella is  so  distinct  from  the  other  two  genera,  that  until  we  have 
definite  evidence  of  the  connection,  it  would  seem  better  to 
maintain  the  genus. 

Family  4.     CYUNDROCAPSACEAE. 

Frond  a  monosiphonous,  rarely  partly  polysiphonous  filament, 
at  first  attached,  later  free,  composed  of  cells  with  parietal  chro- 
matophore  and  one  pyrenoid  ;  asexual  reproduction  by  zoospores 
has  been  reported,  but  is  not  fully  confirmed  ;  akinetes  as  in 
Ulothrix ;  sexual  reproduction  by  antheridia  and  oogonia,  2-4 
antheridia  formed  by  division  of  a  vegetative  cell,  each  anther- 
idium  producing  2  spindle-shaped,  biciliate, -yellowish  spermato- 
zoids,  escaping  through  an  opening  in  the  side  wall ;  oogonium 
formed  from  a  swollen  vegetative  cell,  containing  one  oospore, 
fertilized  by  spermatozoids  entering  by  an  opening  in  the  wall ; 
fertilized  oospore  reddish,  development  unknown ;  the  unferti- 
lized oospore  may  develop  parthenogenetically,  remaining  green, 
and  dividing  to  form  a  new  filament.  Fresh  water.  Only  one 
genus. 

CYLINDROCAPSA  Reinsch,  1867,  p.  66. 

Characters  of  the  family. 

In  its  vegetative  characters  Cylindrocapsa  is  nearly  related  to 
Ulothrix,  but  in  fructification  it  shows  considerable  resemblance, 
and  is  the  only  alga  having  any  considerable  resemblance,  to 
the  Oedogoniaceae. 

C.  GEMINELLA  Wolle,  1887,  p.  104,  PI.  XCI,  figs.  1-17; 
P.  B.-A.,  No.  570.  Filaments  14-16  ^  diam.  (or  more  ?)  subtoru- 
lose,  with  thick,  distinctly  lamellate  wall  ;  oospore  globose, 
about  50  fji  diam.,  lamellate  wall  about  10-15  M  thick.  In  stand- 
ing water,  free  or  adhering  to  other  algae.  Fig.  80.  Mass.  ; 
"  N.  Y.  to  Florida  and  westward,"  Wolle.*  Europe. 

Family  5.     OEDOGONIACEAE. 
Fronds  aquatic,  in  one  European  species  terrestrial,  consisting 

*C.  amoena  Wolle,  1887,  p.  105,  PI.  XCI,  figs.  18-23,  with  filaments  cyl- 
indrical, 7-12  AC  diam.,  cells  2-3  diam.  long,  fructification  by  zoospores  of 
two  sizes,  can  hardly  be  recognized  from  the  description  ;  there  is  really 
nothing  to  indicate  that  it  is  a  Cylindrocapsa. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  223 

of  simple  or  branching  filaments,  of  a  single  series  of  uninucle- 
ate  cells  ;  chromatophores  generally  of  many  longitudinal  bands, 
with  many  pyrenoids  ;  cell  division  by  the  rupture  of  a  circular 
ring,  which  forms  the  membrane  of  the  new  cell.  Asexual  re- 
production by  multiciliate  zoospores,  each  produced  from  the 
entire  contents  of  a  cell,  and  germinating  immediately  ;  also  in 
some  cases  by  akinetes.  Sexual  reproduction  by  oogonia  and 
antheridia  ;  oogonia  single  or  seriate,  formed  by  transformation 
of  vegetative  cells  ;  opening  by  a  lid  or  a  pore  to  admit  the 
spermatozoids ;  when  fertilized  the  oospore  assumes  a  mem- 
brane ;  after  a  period  of  rest  the  oospore  produces  four  zoospores 
(occasionally  fewer  or  more),  which  germinate  at  once.  Anther- 
idia either  in  the  same  filament  with  the  oogonia  or  in  separate 
individuals  ;  male  plants  either  of  about  the  same  si/ed  cells  as 
the  female  plants,  or  much  smaller  ;  in  the  latter  case  the  male 
plants  arise  from  androspores,  similar  to  zoospores  but  smaller ; 
spermatozoids  produced  one  or  two  in  an  antheridium,  smaller 
than  the  androspores,  but  of  similar  appearance.  Fresh  water. 

The  Oedogoniaceae  are  distinct  from  all  other  families,  only 
the  very  small  family  of  the  Cylindrocapsaceae  showing  any 
near  relationship.  There  are  two  genera  of  world-wide  dis- 
tribution, Oedogonium  and  Bulbochaete ;  Oedocladium,  a  mono- 
typic  genus,  is  found  in  Europe. 

The  vegetative  structure  is  of  the  simplest,  but  the  mode  of 
cell  division  is  found  nowhere  else ;  the  reproductive  characters 
are  elaborate  and  varied,  and  the  special  variations  peculiar  to 
the  different  species  seem  to  be  quite  constant.  A  very  thor- 
ough study  of  the  family  has  been  made  by  Hirn,  and  his  mono- 
graph is  the  basis  for  the  following  pages  ;  his  descriptions  have 
been  closely  followed,  few  changes  or  additions  being  required 
for  present  purposes. 

i.     OEDOGONIUM  Link,  1820,  p.  5. 

Frond  of  a  single,  unbranched  series  of  cells,  vegetative  cells 
cylindrical,  rarely  with  constrictions  ;  basal  cell  with  holdfast ; 
terminal  cell  obtuse,  apiculate  or  produced  into  a  long  seta  ;  all 
cells  capable  of  division  ;  oogonia  produced  directly  by  division 
of  a  vegetative  cell. 

In  this  genus  there  are  more  definite  characters  for  distinc- 
tion of  species  than  in  any  other  of  the  larger  genera  of  green 
algae,  and  these  characters  are  quite  constant  in  each  species  ; 
abnormal  developments  are  of  course  to  be  expected,  but  they 


224     TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

can  usually  be  recognized  as  such.  The  chief  difficulty  lies  in 
the  fact  that  different  organs  may  be  distributed  over  two  or 
three  distinct  classes  of  filaments,  and  it  is  by  no  means  easy  to 
get  all  in  the  same  collecting.  Add  to  this  the  fact  that  differ- 
ent species  frequently  grow  together,  so  that  it  is  rather  the  ex- 
ception to  make  a  collection  all  of  one  species,  and  it  will  be 
seen  that  it  is  only  too  easy  to  overlook  one  of  the  forms  of  the 
species  under  consideration,  or  to  mistake  for  it  a  filament  of 
another  species. 

The  peculiarities  of  the  species  of  Oedogonium  require  a  num- 
ber of  special  names  to  be  used  in  the  descriptions,  and  they 
may  be  summarized  as  follows  :  the  antheridia  and  oogonia  may 
occur  on  the  same  filament  (monoecious  species)  or  on  separate  fila- 
ments (dioecious)  ;  in  the  latter  case  the  male  filaments  may  be 
nearly  similar  to  the  female  (macrandrous  species)  or  very  much 
smaller  (nannandrous).  In  the  latter  case  the  male  filaments 
(nannandres,  dwarf  males)  are  minute  plants  of  a  few  cells  each, 
epiphytic  on  the  female  filament,  usually  on  the  oogonium  or 
on  the  cell  below  it  (suffultory  cell).  These  dwarf  males  are 
produced  by  the  germination  of  special  spores  (androspores) 
produced  in  androsporangia  ;  the  androsporangia  are  short  cells, 
usually  narrower  than  the  vegetative  cells  of  the  filaments  in 
which  they  occur ;  they  are  either  single  or  two  or  more  in  a 
series ;  they  occur  in  the  same  filament  as  the  oogonia  (gynan- 
drosporous  species)  or  in  separate  filaments  (idioandrosporous)  ; 
when  the  former  they  may  be  directly  above  the  oogonium  (epigy- 
nous)  or  a  short  distance  above  the  oogonium  (subepigynous),  di- 
rectly below  the  oogonium  (hypogynous),  or  a  short  distance 
below  (subhypogynous).  When  occurring  without  any  reference 
to  the  oogonium  they  are  said  to  be  scattered.  The  dwarf  males 
may  be  unicellular,  the  spermatozoids  being  produced  in  the 
single  cell,  or  pluricellular ;  in  the  latter  case  the  antheridium 
may  be  produced  merely  by  a  partition  forming  in  the  originally 
unicellular  male  (antheridium  interior)  ;  or  in  a  cell  or  in  the 
upper  of  two  or  more  cells  formed  at  the  summit  of  the  male  by 
the  typical  Oedogonium  cell  division  (antheridium  exterior)  ;  in 
this  case  the'part  below  the  antheridium  is  known  as  the  stipe, 
and  may'be  one  to  several  celled.  An  antheridium  may  pro- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  225 

duce  one  or  two  spermatozoids ;  in  the  latter  case  the  sper- 
matozoids  may  be  formed  side  by  side,  with  a  vertical  par- 
tition (division  vertical),  or  one  above  the  other  (division 
horizontal).  The  oogonium  receives  the  spermatozoid  either 
by  a  round  opening  in  the  wall  (poriferous  oogonium),  or  by 
the  upper  part  of  the  oogonium  separating  from  the  lower 
part  by  a  circular  division  all  around  the  wall  (operculate). 
The  pore  may  be  opposite  the  middle  of  the  spore  (pore  median), 
higher  up  (pore  superior),  or  lower  down  (pore  inferior).  In 
the  operculate  species  the  same  distinction  is  indicated  by 
division  median,  superior  or  inferior.  The  membrane  of  the 
oospore  may  consist  of  one  to  three  layers ;  in  the  latter  case 
these  are  known  as  the  outer  membrane  or  exospore,  median 
membrane  or  mesospore,  and  inner  membrane  orendospore.  In 
the  monoecious  species  the  antheridia  occupy  positions  similar 
to  those  of  the  androsporangia  in  the  nannandrous  gynandro- 
sporous  species,  and  are  similarly  known  as  epigynous,  etc. 
The  formation  of  the  spermatozoids  is  the  same  as  in  the  nan- 
nandrous species. 

The  subdivision  of  the  genus  is  largely  artificial ;  the  usual 
division  is  into  monoecious,  dioecious  macrandrous,  and  dioe- 
cious nannandrous  species  ;  but  interesting  parallelisms  may  be 
found  between  the  first  and  third  of  these  series.  There  seem 
to  be  more  species  of  limited  distribution  in  this  genus  than  in 
most  genera  of  green  algae,  but  it  may  be  due  to  imperfect 
knowledge  ;  certainly  some  species  occur  at  widely  distant  sta- 
tions. Undoubtedly  many  species  not  yet  recorded  for  North 
America  will  be  found  here  when  more  attention  is  paid  to  them. 
They  are  all  species  of  quiet  or  slowly  flowing  water,  and  may- 
be found  at  any  time,  except  when  the  water  is  frozen  over. 

KEY  TO  THE  SPECIES  OF  OEDOGONIUM. 

i. ,  Macrandrous.  2. 

i.     Nannandrous.  45- 

2.     Oogonium  opening  by  a  pore.  3. 

2.     Oogonium  opening  by  a  lid.  33. 

3.     Spores  globose.  4- 

3.     Spores  ellipsoid.  17. 

4.     Pore  median.  5- 

4.     Pore  supramedian.  7- 

4.     Pore  superior.  n. 


226 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 


,     Membrane  of  oospore  smooth. 

Membrane  of  oospore  pitted. 

Membrane  of  oospore  spinous. 
6.     Monoecious. 
6.     Dioecious. 

Pore  slightly  above  the  middle. 

Pore  almost  superior. 
8.     Monoecious. 
8.     Dioecious. 

Oogonia  subglobose  or  subdepressed-globose. 

Oogonia  subglobose  or  subellipsoid-globose. 
10.     Monoecious. 
Dioecious. 


10. 


8. 


ii.     Oogonia  manifestly  swollen, 
ii.     Oogonia  little  if  any  swollen. 

12.     Membrane  of  oospore  smooth. 

12.     Membrane  of  oospore  pitted. 
13.     Monoecious. 
13.     Dioecious. 

14.     Vegetative  cells  12-17  //  diam. 

14.     Vegetative  cells  20-30  /x.  diam. 
15.     Monoecious. 
15.     Dioecious. 

16.     Oogonia  K  to  ^  wider  than  vegetative  cells. 

IS- 

16.     Oogonia  scarcely  wider  than  vegetative  cells. 


3.  Oe.  Magnusii. 
4.  Oe.  sue cic inn. 
Oe.  cryptoporum. 
2.  Oe.  rufescens. 


7.     Oe.  cardiaciim. 

5.     Oe.  obsoletmn. 

6.   Oe.  plusiospormn. 

9.  Oe.  varians. 
Oe.  franklin  ian  u  in . 

12. 

IS- 

13- 

13.     Oe.foveolattun. 
14. 
;.     Oe.  plagiostomum. 

10.  Oe.  fragile. 
n.     Oe.  Vaucherii. 

14.     Oe.  geniculatiim. 
16. 


Oe.  capillifortne . 


16. 


17.     Oogonia  manifestly  swollen. 
17.     Oogonia  little  if  any  swollen. 

18.     Membrane  of  oospore  smooth. 

18.     Membrane  of  oospore  ribbed  or  pitted 
19.     Monoecious. 
19.     Dioecious. 

20.     Division  of  antheridial  cell  vertical. 

20.     Division  of  antheridial  cell  horizontal 
21.     Membrane  of  oospore  ribbed. 
21.     Membrane  of  oospore  areolate  or  pitted. 

22.     Ribs  continuous  and  entire. 

22.     Ribs  not  continuous  and  entire. 
23.     Monoecious. 
23.     Dioecious. 

24.     Ribs  composed  of  elongate  dots. 

24.     Ribs  distinctly  dentate. 


Oe.  capillare. 
18. 
27. 
19. 

21. 
2O. 

19.     Oe.  rivularc. 
17.     Oe.  upsaliense. 
18.     Oe.  Richterianmii. 
22. 
25- 
23- 
24. 

20.     Oe.  paludosmn. 
21.     Oe.  Boscii. 
22.     Oe.  margaritiferuin. 
23.     Oe.  crenulato-costaiuni. 


25.     Membrane  of  oospore  areolate. 

23.     Oe.  crenulato-costatum  var.  aureum. 
25.     Membrane  of  oospore  pitted.  26. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  227 

26.     Oogonia  38-48 /u  cliam.  25.     Oe.  pitiictatmit. 

26.     Oogonia  70-83  M  diam.  24.     Oe.  taphrosporuin. 

27.     Membrane  of  oospore  smooth.  28. 

27.     Membrane  of  oospore  pitted.  70.     Oe,  giganteum. 

28.     Monoecious.  26.     Oe.  martinicense . 

28.     Dioecious.  29. 

29.     Oogonia  63-75  /u,  diarn.  27.     Oe.  Landsboroughii. 

29.     Oogonia  65  /u  diam.  or  less.  30. 

30.     Vegetative  cells  3-9  diam.  long.  31. 

30.     Vegetative  cells  i % -3  diam.  long.  31.     Oe.  mexicanuni. 

31.     Oogonia  oboviforrn.  28.     Oe.  oboviforme. 

31.     Oogonia  suboboviform  to  oboviform-ellipsoid.  32. 

32.     Male  plants  stouter  than  female.  29.     Oe.  pachyandriinn. 

32.     Male  plants  more  slender  than  female.  30.     Oe.  grande. 

33.     Oospores  globose.  34. 

33.     Oospores  ellipsoid.  42. 

34.     Division  of  oogonium  median.  35. 

34.     Division  of  oogonium  superior.  36. 

35.     Cells  with  spiral  markings.  32.     Oe.  punctato-striatum. 

35.     Cells  with  walls  plain.  33.     Oe.  Howardii. 

36.     Monoecious.  37. 

36.     Dioecious.  38.     Oe.  Pringsheimii. 

37.     Vegetative  cells  with  three  nodulose  swellings. 

41.     Oe.  nodulosum. 
37.     Vegetative  cells  cylindrical.  38. 

38.     Oogonium  when  inature  pyriform  or  subpyriform.  39. 

38.     Oogonium  when  mature  oboviform-globose  to  subglobose.       40. 
39.     Oogonium  26-30  /j.  diam.  34.     Oe.  Pithophorae. 

39.     Oogonium  40-45  M  diam.  71.     Oe.  pyriforme. 

40.     Oogonia  distinctly  swollen.  41. 

40.     Oogonia  little  swollen.  37.     Oe.  autuntnale. 

41.     Vegetative  cells  15  /x  diam.  or  less.  35.    'Oe.  crispum. 

41.     Vegetative  cells  16  M  diam.  or  more.  36.     Oe.  obe 'sum. 

42.     Membrane  of  oospore  smooth.  43. 

42.     Membrane  of  oospore  ribbed.  42.     Oe.  nobile. 

43.     Oogonia  oblong-ellipsoid  or  ellipsoid.  44. 

43.     Oogonia  pyriform.  72.     Oe.  sanctae  thomae. 

44.     Vegetative  cells  3-7  M  diam.  40.     Oe.  gracillimum. 

44.     Vegetative  cells  10-18  M  diam.  39.     Oe.  Ahlstrandii. 

45.     Dwarf  males  pluricellular.  46. 

45.     Dwarf  males  unicellular.  66. 

46.     Antheridium  exterior.  47. 

46.     Antheridium  interior.  64. 

47.     Oogonium  opening  by  a  pore.  48.. 

47.     Oogonium  opening  by  a  lid.  62. 


228 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 


48.     Oospore  globose. 

48.     Oospore  ellipsoid. 
49.     Pore  median  or  slightly  above. 
49.     Pore  superior. 
49.     Pore  inferior.  52. 

50.     Membrane  of  oospore  smooth. 

50.     Membrane  of  oospore  spinous. 
51.     Oogonium  30-37'^  diam. 
51.     Oogonium  49-53  M  diam. 

52.     Oogonium  subdepressed-globose. 

52.     Oogonium  subglobose  to  ellipsoid.         46. 
53.     Membrane  of  oospore  smooth. 
53.     Membrane  of  oospore  spinous. 

54.     Oogonia  solitary. 

54.     Oogonia  usually  seriate.  59 

55.     Spines  without  order. 
55.     Spines  arranged  spirally. 

56.     Spines  scanty  ;  oogonia  subglobose.  4 

56.     Spines  dense  ;  oogonia  depressed-globose. 
57.     Oogonium  51-64  n  diam.  ;  veg.  cells  15-35  /a  diam. 

50 
57.     Oogonium  63-78  /u.  diam. ;  veg.  cells  32-59  n  diam. 

5i- 

58.     Pore  median  or  slightly  higher. 

58.     Pore  superior. 
59.     Membrane  of  oospore  smooth. 
59.     Membrane  of  oospore  spinous. 

60.     Membrane  of  oospore  smooth. 

60.     Membrane  of  oospore  ribbed. 

60.     Membrane  of  oospore  pitted. 
61.     Suffultory  cell  not  swollen. 
61.     Suffultory  cell  swollen. 

62.     Oospore  globose. 

62.     Oospore  ellipsoid. 
63.     Oogonia  14-23  /u  diam. 
63.     Oogonia  30-56  /u.  diam. 

64.     Oogonium  opening  by  a  pore. 

64.  Oogonium  opening  by  a  lid. 
65.  Membrane  of  oospore  smooth. 
65.  Membrane  of  oospore  ribbed. 

66.     Oospore  globose. 

66.     Oospore  ellipsoid. 
67.     Division  of  oogonium  medium. 
67.     Division  of  oogonium  inferior. 

68 

68 


68. 
Oospore  nearly  or  quite  filling  the  oogonium. 


49- 
58. 
50. 

53; 
Oe.  H until. 

52. 

43.     Oe.  Braunii. 
44.     Oe.  flavescens. 
45.     Oe.  pungens. 
Oe.  echinospermum. 
54- 
55- 

47.     Oe.  irregulare. 
,     Oe.  multisporum. 
56. 

57- 

8.     Oe.  armigenim. 
49.     Oe.  echinatiim. 

Oe.  stellatuni. 

Oe.  Donnellii. 

59- 
60. 

Oe.  sexangulare. 
54.     Oe.  Hystrix. 
61. 

Oe.  Wolleanum. 
Oe.  concatenatum. 
55.     Oe.  crassiusculum. 
56.     Oe.  Borisianuin. 
60.     Oe.  macrandrium. 

63- 

61.     Oe.  longatum. 
62.     Oe.  acrosporum. 

65- 

64.     Oe.  undulatum. 
73.     Oe.  cataractum. 
63.     Oe.  cyathigeruin. 
67. 

69.     Oe.  pluviale. 
68. 

Oe.  platygynum. 
69. 


53- 


57- 
58. 


Ooospore  not  nearly  filling  the  oogonium.    67.    Oe.  Areschougii. 


THE  GREEN  ALGAE  OK  NORTH  AMERICA  229 

69.     Oogouiuni  20-27  M  diatn.  65.     Oe.  Rothii. 

69.     Oogouiuni  30-38  (U  diam.  70. 

70.     Oospore  depressed.  66.     Oe.  decipiens. 

70.     Oospore  globose.  .                  74.     Oe.  londinense. 

MACRANDRIA,  PORIFERA,  GLOBOSPORA. 

1.  OE.  CRYPTOPORUM  var.  vuivGARE  Wittrock,   1874,  p.  7; 
Him,  1900,  p.  73,  PI.  I,  fig.  2  ;  Wolle,  1887,  p.  70,  PI.  LXXIV, 
figs.  1-2;   P.  B.-A.,  No.  1525.     Monoecious;  oogonia  single  or 
more  usually  2-5  seriate,  oboviform-globose   or   depressed-glo- 
bose, opening  by  a   median  pore  ;    oospore  depressed-globose, 
nearly  filling   the   oogonium ;    membrane  smooth  ;    antheridia 
1-4  celled,  subepigynous,  hypogynous  or  scattered;    spermato- 
zoid  single. 

veg.  cell,  5-8    /u  diatn.,  3-6    diam.  long. 

oogonia,  18-23  V-     "  18-26  /j.  long. 

oospores,  16-23  /*     "  J5-X9  M     " 

anth.  cell,  5-7    M     "  9-12  n     " 

Mass., Pa.,  N.  J.,  sec.  Wolle.  Europe,  Australia. 

The  type,  with  somewhat  larger  measurements  in  every  direc- 
tion, oogonia  single,  antheridia  1-7  celled,  occurs  in  northern 
Europe,  but  has  not  been  found  here. 

2.  OE.  RUFESCENS  Wittrock,   1870,  p.  134;  Wolle,  1887,  p. 
89,  PI.  LXXXI,  figs.  16  and  17  ;  Him,  1900,  p.  76,  PI.  I,  fig.  4 ; 
P.  B.-A.,  No.  521.     Monoecious;  oogonia  single  or  2-3,  obovi- 
form-  or  depressed-oboviform-globose,   pore   median  ;    oospore 
globose  or  depressed-globose,  filling  the  oogonium  or  nearly  so, 
membrane  smooth  ;  male  plants  slightly  more  slender  than  the 
female  ;  antheridia  up  to  i2-celled  ;  spermatozoid  single. 

veg.  cell,  female,         S-io/udiam.,         4-7    diam.  long. 

veg.  cell,  male,  7-9    M      "  4-6 

oog.,  22-24  A*      "  22-30  /x  long. 

oos.,  21-23  /u,      "  17-22  M     " 

anth.  cell,  6-8    /x      "  8-12  f    " 

R.  I.,  Conn.  Europe. 

Subsp.  LUNDELLII  (Wittr.)  Him,  1900,  p.  77,  PI.  I,  fig.  6; 
P.  B.-A.,  No.  1428.  Oogonia  and  oospores  more  depressed, 
the  former  subdepressed-  or  depressed-globose  ;  vegetative  cells 
somewhat  shorter  and  in  comparison  with  the  oogonia  somewhat 
stouter  than  in  the  type  ;  oogonia  solitary  or  two. 

veg.  cell,  female,      tg-i2  M  diam.,         3-4^  diam.  long. 

veg.  cell,  male,  8-10  /*      "  3-4 

oog.,  22-25  M      "  23-27  A*  l°ng- 

OOS.,  19-23  /U        "  15-22  fJ.      ' 

anth.  cell,  7-8    M      "  6-12 /x    " 

Maine,  Cal.  Europe. 


230          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

3.  OE.  MAGNUSII  Wittrock,  1874,  p.  38;  Hirn,  1900,  p.  81, 
PI.  II,  fig.   14;    Wittr.  and   Nordst.,  Alg.   Exsicc.,   No.    109. 
Dioecious ;   oogonia   single,    rarely  2,  depressed-globose,    pore 
median  ;    oospore  same  form   as  oogonium  and  fully  filling  it, 
with  triple  membrane  ;    median  pitted,  others  smooth  ;   anther- 
idia  up  to  8-celled  ;  spermatozoid  single. 

veg.  cell,  7-10  M  diam.,          1/4-4    diam.  long, 

oog.,  24-27  n    "  21-26  n  long. 

OOS.,  22-25  M      "  18-23  fJ.      " 

anth.  cell,  8-10  M     "  5-n  M     " 

Mass.  Northern  Europe. 

4.  OE.  SUECICUM  Wittrock,  18723,  p.  5;   Hirn,  1900,  p.  82, 
PI.  II,  fig.  15.     Dioecious  ;  oogonia  single,  subglobose,  rarely 
ellipsoid-globose,  pore  median ;  oospore  globose,   nearly  filling 
the   oogonium ;    epispore   with   subulate   spines  ;     male   plants 
about  the  same  size  as  the  female  or  slightly  smaller ;  anther- 
idium  2-4-?-celled,  generally  in  the  upper  part  of  the  filament ; 
spermatozoid  single  ?  ;  basal  cell  elongate,  terminal  cell  obtuse. 

veg.  cell,  9-14  fj.  diam.,          3-7    diam.  long, 

oog.,  32-38  /JL     "  18-26  fj.  long, 

oos.  with  spines,       30-37  n    "  3<>37  M     " 

anth.  cell,  10-12  M     "  9-12  n     " 

Mass.  Europe,  Australia. 

The  only  macrandrous  dioecious  species  with  spinous  oospores. 

5.  OE.  OBSOLETUM  Wittrock,    1874,  p.   9;    Wolle,   1887,  p. 
71,   PI.  LXXIV,    fig.  3,    PI.   LXXVI,   figs.   6  and  7  ;   Hirn, 
1900,  p.  83,  PI.  II,  fig.  16.     Monoecious;  oogonia  single,  sub- 
globose  or  depressed  globose,  pore  slightly  above  the  middle ; 
oospore   globose   or   depressed-globose,    not   quite    filling    the 
oogonium,  membrane  smooth  ;  antheridia   1-3  celled,  subepigy- 
nous  ;  spermatozoid  single. 

veg.  cell,  9-15  M  diam.,  3-5    diam.  long. 

oog.,  34-39  M      "  34-43  M  long. 

oos.,  30-34  n      "  28-32  n    " 

anth.  cell,  8-9    M      "  12-16  AC     " 

Pa.  Siveden. 

This  species  and  the  following  are  included  only  on  account 
of  Wolle's  reference,  which  is  quoted  as  to  this  species  with  a  ? 
by  Hirn.  The  two  following  species  closely  resemble  it.  Oe. 
obsoletum  and  Oe.  plusiosporum  are  monoecious ;  Oe.  cardiacum 
is  dioecious,  and  of  somewhat  larger  dimensions.  Oe.  obsoletum 
generally  has  longer  vegetative  cells  than  the  others,  and 
oogonia  shorter  than  their  diameter,  while  Oc.  plusiosporum  has 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  231 

a  stouter  aspect,  and  almost  ellipsoidal  oogonia.  Oc.  cardiacuni 
has  two  spermato/oids  in  each  antheridial  cell,  the  others  one 
spermatozoid  only. 

6.  OE.  PLUSIOSPORUM  Wittrock,   1874,  p.  u  ;  Wolle,    1887, 
p.  72,  PI.  LXXIV,  figs.  20  and  21;  Him,    1900,  p.  84,   PI.  II, 
fig.  17.     Monoecious;  oogonia  single,  subglobose  or  ellipsoid- 
globose,    pore   slightly  above   the  middle ;    oospore  globose  or 
nearly  so,  not   quite  filling  the  oogonium,  membrane  smooth  ; 
antheridia    up    to   6-celled,   subepigynous,    subhypogynous,    or 
scattered  ;   spermatozoid  single  ;  terminal  cell  obtuse. 

veg.  cell,  12-19  M  diam.,  2-4    diam.  long, 

oog.,  34-45  /j,    "  35-50  fj.  long, 

oos.,  30-39  p.    "  30-39  M    " 

anth.  cell,  12-14  M     "  8-12  M     " 

Pa.,  N.  J.,  Cal.  Northern  Europe. 

7.  OE.  CARDIACUM  (Hass.)  Wittrock,   1870,  p.   135;  Him, 
1900,  p.  85,  PI.   Ill,  fig.   19.     Dioecious;  oogonia  single,   very 
rarely    2,    subglobose    or    subcordiform-globose,    pore   slightly 
above  the  middle  ;  oospore  globose,    not  filling   the  oogonium, 
membrane  smooth ;    male   plants    slightly    more   slender   than 
the    female  ;    antheridia  up  to  lo-celled,  spermatozoids  binate, 
division  horizontal ;   basal  cell  elongate,   terminal  cell  obtuse. 

veg.  cell,  female,       18-30  /j.  (Ham.,  3-7    diam.  long. 

veg.  cell,  male,          15-25  /"•     "  3-7       " 

oog.,  48-70  fj.    "  58-78  M  long. 

oos.,  42-60,11     "  42-60 /a     " 

anth.  cell,  15-21  /a    "  10-14  M     " 

Pa.,  Ontario.  Europe,  Africa,  So.  America. 

The  range  in  dimensions  is  considerable ;  in  most  cases  the 
plants  approach  the  lower  limit,  only  rarely  the  upper. 

Var.  CARBONICUM  Wittrock,  in  Wittr.  and  Nordst.,  Alg.  Ex- 
sicc.,  No.  504;  Him,  1900,  p.  87,  PI.  IV,  fig.  22,  is  reported 
from  Iowa  by  Wolle,  1887,  p.  90,  PI.  lyXXXII,  figs.  14  and  15. 
It  has  oogonia  not  uncommonly  double,  oboviform  or  globose- 
oboviform,  pore  higher  than  in  the  type,  oospore  the  same  form 
as  the  oogonium,  and  not  quite  filling  it. 

8.  OE.  FRANKLINIANUM  Wittrock,  in  Wittr.  and  Nordst., 
Alg.  Exsicc.,  No.  309;  Wolle,   1887,  p.  89,  PL  LXXXII,  figs. 
7-9;   Him,    1900,  p.  88,    PI.    II,   fig.   18.     Dioecious;    oogonia 
single  (very  rarely  2),  subglobose  (or  sub-ellipsoid-globose),  pore 
superior  ;  oospore  globose,  almost  filling  the  oogonium,  mem- 
brane smooth  ;  male  plant  rather  more  slender  than  the  female  ; 
antheridia  i-3-celled  ;  spermatozoids  2,  division  horizontal. 


veg.  cell,  female, 

9-12  /x  diam., 

veg.  cell,  male, 

8-10  /*     " 

oog., 

26-31  M      " 

COS., 

24-30  /x      " 

anth.  cell, 

8-9    /*     " 

N.  J.,  Pa. 

232  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

3-8    diam.  long. 
3-9        " 
29-4i  /x  long. 

24-30  il        " 

5-7    /x      " 

So.  America. 

Resembling  Oe.  cardiacum,  but  a  more  slender  plant,  and  with 
pore  higher  up  on  the  oogonium. 

9.  OE.  VARIANS  Wittrock  and  L,und  in  Wittrock,  1874,  p. 
ii ;  Hirn,  1900,  p.  89,  PL  IV,  fig.  23;   Oe.  polymorphum  Wolle, 
1887,  p.  73,   PI.   L/XXIV,   figs.   16-19.     Monoecious;  oogonia 
single,    very   rarely    2,    depressed-    or    subdepressed-pyriform- 
globose,  pore  nearly  superior ;  oospore  globose,   not  filling  the 
oogonium,  membrane  smooth  ;  antheridia  to  g-celled,  scattered  ; 
spermatozoids  binate,  division  horizontal ;  basal  cell  elongate, 
terminal  cell  obtuse. 

veg.  cell,  12-16  /u  diam.,  3-9    diam.  long. 

oog.,  35-50  /x     "  34-55  M  long. 

oos.,  31-41  M     "  3°-4i  M     " 

anth.  cell,  11-15  M     "  5-7    M     " 

N.  J.  Europe. 

Characterized  specially  by  the  high  position  of  the  pore,  and 
by  the  antheridia,  in  series  of  several,  irregularly  placed  among 
the  vegetative  cells. 

10.  OE.  FRAGILE  Wittrock,  1870,  p.  120;  Wolle,  1887,  p.  71, 
PI.  LXXIV,  figs.  4-6  ;  Him,  1900,  p.  96,  PI.  V,  fig.  33  ;  P.  B.-A., 
No.  1477.     Monoecious;    oogonia  single,  globose  or  subobovi- 
form-globose,  pore  superior ;    oospore  globose,  filling  the  oogo- 
nium, membrane  smooth  ;    antheridia  i-3-celled,  hypogynous  or 
subepigynous  ;  spermatozoids  binate,  division  horizontal ;  basal 
cell  elongate.    Fig.  81. 

veg.  cell,  12-17  M  diam.,  4-7    diam.  long. 

oog.,  42-50 /x     "  44-55  M  long. 

oos.,  39-46  /x    "  39-46  /x     " 

anth.  cell,  12-15  M     "  10-12  M     " 

Mass.,  Pa.  Europe. 

Beside  the  type,  Hirn  notes  and  figures,  PI.  VI,  fig.  34,  a 
form,  not  named,  from  Massachusetts,  with  dimensions  of  cells, 
oogonia  and  oospores  about  3  ^  more  than  the  type ;  the  an- 
theridia may  be  up  to  6  in  a  series,  occurring  irregularly  in  the 
filament. 

11.  OE.  VAUCHERII  (L,eCl.)  A.  Braun,   18553,  p.  40,  PL  II, 
fig.  13;  Hirn,  1900,  p.  97,  PL  VI,  fig.  36;  Wittr.  and  Nordst., 


THE  GREEN  ALGAE  OF  NORTH  AMERIC\  233 

Alg.  Exsicc.,  No.  20.  Monoecious  ;  oogonia  single,  oboviform  or 
suboboviform-globose,  pore  superior ;  oospore  globose  or  sub- 
globose,  not  quite  filling  the  oogonium,  membrane  smooth, 
usually  thick  ;  antheridium  up  to  4-celled,  subepigynous  or 
hypogynous  ;  spermatozoids  binate,  division  horizontal ;  basal 
cell  elongate. 

veg.  cell,  2030  /j.  diain.,          i%-4    diam.  long. 

oog.,  40-55  /j.     "  45-65  fj.  long. 

oos.,  35-50  M     "  35-52  M     " 

anth.  cell,  17-24  M     "  6-n /u.     " 

Mass.  Europe,  Asia. 

Resembling  Oc.  fragile,  but  with  vegetative  cells  stouter 
and  shorter,  while  the  oogonia  are  of  about  the  same  size. 

12.  OE.  PLAGIOSTOMUM  var.  GRACILIUS  Wittrock,  1878,  p. 
142;  Him,   1900,  p.  101,  PI.  VI,  fig.  40.     Dioecious;  oogonia 
single,   oboviform-globose,   pore   superior ;    oospore  globose   or 
sub-globose,  about   filling   the   oogonium,  with  thick,    smooth 
membrane ;    male  plant   about   the   same   size   as  the  female ; 
antheridia    i-5-celled,  often  alternating  with  vegetative  cells; 
basal  cell  elongate. 

veg.  cell,  female,      20-25  /*diam.,  2-3^  diam.  long. 

veg.  cell,  male,         20-23  /*    "  2-4      " 

oog.,  36-42  M     "  46-57  M  long. 

oos.,  34-39  M     "  36-44  M     " 

anth.  cell,  19-22/1*    "  7-10  M     " 

N.  Y.,  Mexico. 

The  type,  with  vegetative  cells  about  2  //.  thicker,  oogonia  and 
oospores  7  /*  more  diam.,  occurs  in  Europe;  the  dimensions 
given  above  are  for  Mexican  specimens ;  those  from  Ithaca, 
N.  Y.,  have  cells  a  little  more  slender. 

13.  OE.  FOVEOLATUM  Wittrock,   1878,  p.   133;  Him,   1900, 
p.  106,  PI.  VII,  fig.  46.     Monoecious;  oogonia  single,  rarely  2, 
oboviform-  or  subellipsoid- globose,  pore  superior  ;  oospore  glo- 
bose or  subellipsoid-globose,  filling  or  not  quite  filling  the  oogo- 
nium, membrane 'double,   outer  with  net-like  markings,  inner 
smooth ;    antheridia  i-7-celled,   hypogynous,   subepigynous,  or 
scattered  ;   spermatozoids  binate,  division  horizontal ;  basal  cell 
elongate,  terminal  cell  obtuse. 

veg.  cell,  14-23  M  diam.,  2^-5  diam.  long, 

oog.,  37-49  /*    "  38-57  /« long, 

oos.,  33-46  fi    "  34-48  M    ' 

anth.  cell,  15-19  M    "  8-12  M    " 

St.  Thomas.  So.  America^ 


234  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

The  net-like  marking  of  the  spores  is  found  in  some  other 
species,  but  the  only  one  with  which  there  is  any  danger  of  mis- 
take is  Oe.  scrobiculatum ,  which  can  be  distinguished  by  being 
dioecious,  and  having  ellipsoid  spores. 

14.  OE.  GENICULATUM  Hirn,  1898,  p.  28  ;    1900,  p.  106,  PI. 
VIII,  fig.  48  ;   P.  B.-A.,  No.  411.     Monoecious  ;  oogonia  single, 
slightly  swollen,  oboviform  or  oboviform-globose,  pore  superior ; 
oospore    not   filling   the    oogonium,  globose   or   sub-depressed- 
globose,    sometimes    appearing    subquadrangular ;     membrane 
thick,  smooth;    antheridia   i-5-celled,   subepigynous,  subhypo- 
gynous  or  scattered,  often  alternating  with  vegetative  cells. 

veg.  cell,  37-48  /a,  diatn.,  i>£-3    diam.  long. 

oog.,  56-63  AI     "  56-67  /u  long. 

oos.,  48-59  M    "  48-59  n    " 

anth.  cell,  37-44  M     "  5-9    p     " 

California. 

Noticeable  in  this  species  is  the  fact  that  the  oogonia  pro- 
ject but  little  beyond  the  vegetative  cells ;  a  few  other  species 
are  similar,  but  they  are  all  dioecious. 

15.  OE.  CAPILLIFORME  Kiitzing,  1849,  p.  367  ;  Wolle,  1887, 
p.   88,    PI.   LXXV,   figs.    11-13;  Hirn,   1900,  p.  107,  PI.  VIII, 
fig.  49  ;   Rourneguere,   Alg.   Exsicc.,  No.   685,  as  Oe.  cap i Hare. 
Dioecious;    oogonia  single,  slightly  swollen,  oboviform  or  sub- 
oboviform,  pore  superior ;    oospore   ellipsoid-globose   or   cylin- 
drical-globose.  and  appearing  quadrangular,  sometimes  with  a 
slight  constriction  at  the  middle,  more  rarely  globose  or  sub- 
globose,  not   filling   the   oogonium,    membrane  smooth ;    male 
plant   slightly  more   slender  than  the  female  ;  antheridia  2-5-, 
rarely   lo-celled,   often    alternating  with    the  vegetative    cells ; 
spermatozoids  binate,,  division  horizontal;  basal  cell  elongate, 
terminal  cell  obtuse  or  apiculate. 

veg.  cell,  female,  28-38  M  diam.,  1/^-3    diam.  long, 

veg.  cell,  male,  25-30  M     "  J^-3       "          " 

oog.,  42-50  n     "  51-62  fj.  long, 

oos.,  37-45  /x     "  40-50  n     " 

anth.  cell,  20-25/4     "  8-10  M     " 

Reported  by  Wolle,  but  questioned  by  Hirn  as  to  being  of  the 
type.  From  St.  L,ouis,  Mo.,  is  recorded  a  forma  valida,  one- 
seventh  to  one-tenth  larger. 

Var.  AUSTRALE  Wittrock  in  Wittr.  and  Nordst.,  Alg.  Exsicc., 
No.  704;  Hirn,  1900,  p.  109,  PI.  IX,  fig.  52;  P.  B.-A.,  No. 
1189;  Oc.  princeps  Wolle,  1887,  p.  93,  PI.  LXXVIII,  fig.  3 ; 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  235 

Oc.  stagnate  Wolle,  1887,  p.  88,  PI.  LXXXIII,  figs.  3-6. 
Oogonia  slightly  less  swollen  and  usually  a  little  shorter,  obovi- 
form-globose  or  sub-globose  ;  oospore  globose  or  subglobose ; 
dimensions  between  the  type  and  forma  valida.  N.  Y.,  Mex- 
ico, So.  Dakota,  Minn.,  Montana,  Neb.,  Cal.,  Vancouver. 

Africa,  So.  America. 

Forma  DIVERSUM  Hirn,  1900,  p.  no,  PI.  IX,  fig.  54;  Oe. 
stagnate  Tilden,  Amer.  Algae,  Nos.  122,  545.  A  robust  form, 
with  oospores  varying  from  depressed-globose  to  cylindric-glo- 
bose  ;  filaments  a  third  to  a  fourth  larger  than  in  the  type. 
Colorado,  Montana,  Minn. 

Forma  DEBARYANUM  (Chmiel.)  Hirn,  1900,  p.  108,  PI.  VIII, 
fig.  50.  Oospore  usually  globose  or  subglobose,  rarely  cylin- 
drical-globose, 38-50  /A  diam.,  40-53  p  long;  other  dimensions 
slightly  smaller  than  in  the  type.  Greenland.  Russia. 

A  variable  species,  a  number  of  other  forms  occurring  in 
other  countries  ;  we  have  no  species  for  which  it  is  liable  to  be 
mistaken,  if  the  organs  of  both  sexes  are  well  developed. 

16.  OE.  CAPILI.ARE   (Iy.)  Kiitzing,    1843,  p.  255,   PL   XII, 
figs,  i-io;  Wolle,    1887,  p.  87,  PL  LXXXIII,  figs.  7  and  8; 
Hirn,  1900,   p.   112,   PL  XI,  fig.  58.     Dioecious;  oogonia  sin- 
gle, little  or  not  at  all  swollen,  cylindrical  or  subcylindrical, 
pore  superior ;    oospore   not   filling   the   oogonium,  globose  or 
somewhat  cylindric-globose,   sometimes  slightly  constricted   at 
the  middle,  rarely  depressed-quadrangular-globose,  membrane 
smooth  ;  male  plant  about  the  same  size  as  the  female  or  slightly 
less;    antheridia   i-4-celled,  usually  alternating  with  vegetative 
cells ;    spermatozoids    binate,    division    horizontal ;    basal   cell 
elongate,  terminal  cell  obtuse  or  short-apiculate. 

veg.  cell,  female,      38-55  M  diam.,  1-2    diam.  long, 

veg.  cell,  male,          35-50  ft    "  1-2       " 

oog.,  40-60 /x     "  45-75  M  long, 

oos.,  30-52  ft.    "  36-65  ft    ' 

anth.  cell,  30-48  ft    "  5-10  ft    " 

Only  known  here  by  the  general  report  by  Wolle,  without 
locality.  Europe. 

MACRANDRIA,  PORIFERA,  ELLIPSOSPORA. 

17.  OE.  UPSALIENSE  Wittrock,  1870,  p.  125;  Hirn,  1900,  p, 
115,  PL  XII,  fig.  60;  Wittr.   and  Nordst.,  Alg.  Exsicc.,  No. 
1 8.     Monoecious ;    oogonia    single,    oboviform    or    suboblong- 
ellipsoid,  pore  superior ;  oospore  same  form  as  the  oogonium, 
filling  the  latter,  membrane  smooth;  antheridia  1-2- (rarely  3-) 
celled,  subhypogynous  ;  antheridia,  oogonia  and  vegetative  cells 


236          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

often  alternating ;  spermatozoids  binate,  division  vertical ;  vege- 
tative cells  varying  much  in  diameter  in  the  same  filaments ; 
suffultory  cells  often  larger  and  shorter  than  the  others ;  basal 
cell  elongate,  terminal  cell  obtuse. 

veg.  cell,  13-20  M  diam.,  4-8      diatn.  long. 

oog.,  45-5O  M     "  66-100  /a  long. 

COS.,  42-47  M      "  60-75     M      " 

anth.  cell,  15-18  M     "  7-10    /u     " 

Greenland,  N.  H.,  Michigan.  Europe. 

A  special  character  of  this  species  is  the  variation  in  size  of 
the  cells  in  the  same  filament.  The  cells  under  the  oogonia  are 
the  stoutest  and  shortest,  those  directly  over  the  oogonia  the 
longest  and  most  slender.  The  antheridial  cells  are  very  sel- 
dom over  2  in  a  series. 

18.  OE.   RICHTERIANUM    I,emmerman,    1895,    p.    26,    figs. 
1-3;   Him,    1900,  p.  117,   PI.  XII,  fig.  63  ;   P.  B.-A.,  No.  1429. 
Monoecious  ;    oogonia  single  or  2,   oboviform  or  subellipsoid, 
pore   superior ;    oospore   suboboviform    or  subellipsoid,    rarely 
globose-ellipsoid,   quite  or  nearly  filling  the  oogonium,   mem- 
brane smooth;    antheridia    i-6-celled,  subhypogynous,  subepi- 
gynous  or  scattered  ;  spermatozoids  binate,  division  horizontal ; 
basal  cell  usually  elongate. 

veg.  cell,  12-21  M  diam.,  3-6^  diam.  long, 

oog.,  36-48  /x     "•  48-74    Mlong. 

oos.,  35-43  M     "  43-59    M     " 

anth.  cell,  12-15  M    "  6-9      M     " 

Mass.  Europe. 

19.  OE.  RIVULARE  (LeCl.)  A.  Braun,    i855a,  p.  23,   PI.  I, 
figs,  i-ie;   Wolle,    1887,  p.   92,   PI.  LXXXIII,  figs,  i   and  2  ; 
Hirn,    1900,   p.    119,   PI.  XII,   fig.   66;   Phyk.   Univ.,   No.   70. 
Dioecious;     oogonia    single     or    2-7-seriate,    oboviform,    pore 
superior  ;  oospore  oboviform,  ellipsoid  or  subglobose,  not  nearly 
filling  the  oogonium,  membrane  smooth;  male  plant  somewhat 
more  slender  than  the  female  ;  antheridia  to   i3-celled  ;  sperma- 
tozoids binate,  division  horizontal ;  basal  cell  elongate. 

veg.  cell,  female,      35-45 /x  diam.,  3-8    diam.  long. 

veg.  cell,  male,          30-3611     "  4-8      "          " 

oog.,  70-85/11     "  130-160  /x  long. 

oos.,  55-yo/i     "  65-10011     " 

anth.  cell,  21-28  M     "  14-26    /u     " 

Iowa,  Florida.  Northern  Europe. 

A  large  species,  easily  recognizable  by  the  size,  the  oogonia 
many  in  a  series,  and  the  oospore  much  smaller  than  the  oogo- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  237 

uiutii ;  the  autheridia  are  usually  many  in  a  series.  Wolle's 
reference  appears  to  be  the  only  authority  for  its  occurrence  in 
America. 

20.  OE.  PALUDOSUM  (Hass.)  Wittrock,  1870,  p.  124;  Wolle, 
1887,  p.  74,  PI.  LXXV,  fig.  i  ;  Him,   1900,  p.   120,  PI.  XIII, 
fig.  69.     Monoecious ;  oogonia  single,  ellipsoid,  pore  superior  ; 
oospore  ellipsoid,  filling  the  oogonium,  membrane  triple,  outer 
and  middle  layers  with  longitudinal  lines,  27-35  i'1  number,  con- 
tinuous, rarely  anastomosing ;    antheridia   i-8-celled,   scattered, 
often  in  the  upper  part  of  the  filament ;   spermatozoids  binate, 
division  vertical. 

veg.  cell,  15-20  M  diam.,  3-7    diam.  long, 

oog.,  39-48/14     "  66-84  M  long 

oos.,  36-45  M    "  54-63  n    " 

anth.  cell,  14-16  /u.     "  6-13  /a     " 

Type  reported  by  Wolle  from  Pa.,  but  questioned  by  Him. 

Northern  Europe, 

Var.  AMERICANUM  Nordstedt  in  Him,  1900,  p.  121,  PI.  XIII, 
fig.  72.  Oogonia  larger,  ellipsoid;  oospore  of  same  shape,  fill- 
ing the  oogonium. 

veg.  cell,  14-23  fj.  diam.,  3-7    diain.  long, 

oog.,  54-63  fj.    "  75-90  fi  long, 

oos.,  49-57  M    "  69-75  V-    " 

anth.  cell,  12-18  n    "  7-12  /u     " 

So.  Carolina. 

The  peculiar  sculpture  of  the  spore  is  sufficient  to  distinguish 
this  and  the  following  species  from  all  others.  The  outer  sur- 
face of  the  external  membrane  is  smooth,  but  its  inner  surface 
and  the  outer  surface  of  the  median  membrane  are  marked  with 
longitudinal  lines,  arranged  like  the  meridians  of  a  sphere. 
The  two  species  are  distinct  in  the  arrangement  of  the  organs  of 
fructification,  Oe.paludosum  being  monoecious,  Oc.  Boscii  dioe- 
cious. 

21.  OE.    BOSCII    (LeCl.)    Wittrock,    1870,  p.    136;    Wolle, 
1887,  p.  91,  PI.  LXXXII,  figs.  11-13;  Him,   1900,  p.   122,  PI. 
XIII,  fig.  73;    Wittr.,  Nordst.  and  Lagerh.,  Alg.  Exsicc.,  No. 
1213.     Dioecious;    oogonia  single  (very  rarely  double)  oblong- 
ellipsoid,  pore  superior;  oospore  ellipsoid,  not  nearly  filling  the 
oogonium  ;  marked  as  in  Oe.  paludosum  ;  male  plant  somewhat 
more  slender  than  the  female. 


238          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

veg.  cell,  female,       14-23  M  diain.,  3-6    diam.  long, 

veg.  cell,  male,          13-18^     "  4-6        "         " 

oog.,  39-51  ^     "  75-110  M  long. 

COS.,  36-43  M      "  56-70     /u      " 

anth.  cell,  13-14  M     "  6-16    /a    " 

Greenland,  Mass.,  Conn.,  Cal.  Europe,  So.  America.. 

Forma  DISPAR  Hirn,  1900,  p.  124,  PI.  XIV,  fig.  76  ;  P.  B.-A., 
No.  1226.  Oospore  smaller,  ellipsoid-globose  or  sub-globose; 
oogonia  shorter,  sometimes  suboviform. 

veg.  cell,                     14-21  fj.  diam.,  4-7    diam.  long. 

oog.,                            38-45  M     "  7°-92  M  long. 

oos.,                             34-43  /*     "  44-55  M     " 
Mass.,  Pa.,  Cal. 

Var.  OCCIDENTALE  Hirn,  1900,  p.  125,  PI.  XIV,  fig.  77. 
More  slender  in  all  parts,  vegetative  cells  longer  ;  male  plant 
same  diameter  as  the  female. 

veg.  cell,  female,        8-15  /j.  diam.,  6-n    diam.  long. 

veg.  cell,  male,  8-15  M     "  6-n     "        " 

oog.,  33-38  M     "  75-100  M  long. 

oos.,  32-37^     "  45-5°    M     " 

anth.  cell,  12-13  M     "  10-16    n     " 

Kittery,  Maine. 

22.  OE.  MARGARITIPERUM  Nordstedt  and  Hirn  in  Hirn, 
1900,  p.  128,  PI.  XV,  fig.  83.  Dioecious;  oogonia  single,  sub- 
oblong  or  suboviform-ellipsoid  or  subellipsoid,  pore  superior ; 
oospore  ellipsoid  or  globose-ellipsoid,  not  nearly  filling  the 
oogonium,  or  rarely  nearly  filling  it ;  membrane  triple,  with 
longitudinal  lines  on  the  inner  surface  of  the  outer  membrane 
and  the  outer  surface  of  the  median  membrane ;  lines  30-35, 
sometimes  anastomosing,  not  continuous,  but  made  up  of  some- 
what elongate  dots ;  male  plant  somewhat  more  slender  than 
the  female  ;  antheridia  to  lo-celled  ;  spermatozoids  binate,  divi- 
sion vertical. 

veg.  cell,  female,      23-28  M  diam.,  3/4-7    diam.  long. 

veg.  cell,  male,          17-23  M     "  4/4-7        "         " 

oog.,  50-63  M     "  82-100  M  long. 

oos.,  48-61  M     "  55-75    M     " 

anth.  cell,  18-20  M    "  7-13    M     " 

So.  America. 

Hirn  considers  as  probably  belonging  to  this  species  the  plant 
figured  by  Wood,  1872,  PL  XVIII,  fig.  4,  but  not  named,  and 
on  this  probability  it  is  here  included.  It  varies  considerably 
in  the  size  and  shape  of  the  oogonium  and  oospore,  but  on  care- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  239 

ful  examination  should  be  easily  distinguished  by  the  dotted, 
not  continuous  "  meridians"  on  the  spore. 

23.  OE.      CRENULATO-COSTATUM     Wittrock,     1878,    p.     139; 

Hirn,  1900,  p.  129,  PI.  XV,  fig.  84;  P.  B.-A.,  Nos.  810,  1426. 
Dioecious;  oogonia  single  or  2-3,  rarely  4-5,  oboviform  or 
subellipsoid,  rarely  oblong-ellipsoid,  pore  superior;  oospore 
same  form  as  the  oogonium,  filling  or  nearly  filling  the  latter, 
membrane  triple,  external  membrane  smooth,  median  mem- 
brane with  14-20  longitudinal,  crenulate,  sometimes  anastomos- 
ing lines  ;  male  plant  somewhat  more  slender  than  the  female  ; 
autheridia  2-6-celled,  often  alternating  with  vegetative  cells  ; 
spermatozoids  binate,  division  horizontal ;  terminal  cell,  which 
not  infrequently  is  an  oogonium,  obtuse  or  short-apiculate. 

veg.  cell,  female,      10-18  /u.  diatn.,         2^-7    diam.  long. 

veg.  cell,  male,  9-13  M     "  3>£-6        " 

oog.,  30-36  M     "  40-65  M  long. 

oos.,  28-34  M     "  37-55  V-    " 

anth.  cell,  9-12  M     "  9-14  M     " 

Mass.,  Conn.,  N.  Y.,  Pa. 

Forma  CYLINDRICUM  Hirn,  1900,  p.  129,  PI.  XV,  fig.  85  ; 
P.  B.-A.,  No.  118,  as  Oe.  Bosrii.  Ooogonia  and  oospores  of 
variable  form,  generally  cylindric-oblong,  rarely  ellipsoid  or 
obovate-ellipsoid ;  longitudinal  lines  slightly  crenate  or  almost 
entire  ;  oogonia  single  or  2-4  ;  vegetative  cells  slender. 

veg.  cell,  11-16  n  diam.,  4-10  diam.  long. 

oog.,  30-36  M     "  42-81  M  long. 

oos.,  2  7-34  M     "  40-65  /j.    " 

Mass.,  Conn.,  Mo. 

Var.  AUREUM  Tilden,  Amer.  Algae,  No.  123;  1898,  p.  90, 
PI.  VIII,  fig.  1-3  ;  Hirn,  1900,  p.  130,  PI.  XV,  fig.  87.  Slender, 
oogonia  shorter  than  in  the  type,  single  or  2-3  ;  oospore  obovoid 
to  globose-ellipsoid,  not  quite  filling  the  oogonium  ;  lines  of  the 
oospore  only  scantily  toothed,  connected  by  distinct  cross-lines. 

veg.  cell,  10-13  M  diam.,         3/^-9    diam.  long. 

oog.,  3°-35  M     "  38-50  M  long. 

oos.,  29-33  M     "  35-43  P    " 

In  warm  water,  Yellowstone  National  Park. 

The  peculiar  character  of  the  "meridians"  identifies  this 
species  in  its  various  forms,  much  as  the  latter  differ  in  other 
particulars.  Hirn  thinks  it  probable  that  under  this  name 
should  be  included  Oe.  apiculatum  Wolle,  18773,  p.  188. 

24.  OE.  TAPiiROSroRUM  Nordstedt  and  Hirn  in  Hirn,  1900, 


240          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

p.  133,  PI.  XVI,  fig.  91;  P.  B.-A.,  No.  813.  Dioecious; 
oogonia  2-6  or  single,  obovlform  or  oboviform-ellipsoid,  pore 
superior ;  oospore  globose  or  ellipsoid-globose,  not  filling  or 
nearly  filling  the  oogoniutn,  membrane  double,  outer  membrane 
pitted,  inner  smooth ;  male  plants  about  the  same  size  as  the 
female  ;  antheridium  2-?-celled  ;  terminal  cell,  which  sometimes 
is  an  oogonium,  obtuse. 

veg.  cell,  female,      25-38  ^  diani.,  4-10    diam.  long. 

veg.  cell,  male,         26-33  M     "  4-9          "        " 

oog.,  70-83**     "  81-113  M  long. 

oos.,  58-65  M     "  62-70    /x     " 

anth.  cell,  24-32  n    "  8-12    /x     " 

Mass.  So.  America. 

25.  OE.  PUNCTATUM  Wittrock,   1878,  p.   142;    Him,    1900, 
p.   132,   PL   XV,  fig.  89.      Dioecious;    oogonia   2-4-seriate   or 
single,    oboviform,    rarely    globose-oboviform,    pore    superior ; 
oospore  oboviform,  almost  filling  the  oogonium,  rarely  subglo- 
bose,  and   then   not   filling  the   oogonium,  membrane  double, 
outer  membrane  densely  pitted,  inner  membrane  smooth  ;  male 
plants  about   the   size   of  the  female;    antheridia    i-5-celled, 
often    alternating    with    the   vegetative    cells  ;     spermatozoids 
binate,  division  horizontal ;  basal  cell  elongate  ;  terminal  cell, 
which  is  frequently  an  oogonium,  obtuse. 

veg.  cell,  female,      15-22  ^diam.,  3-6    diam.  long. 

veg.  cell,  male,          15-22  /x     "  3-6        "        " 

oog.,  38-45  /*     "  52-65  M  long. 

oos.,  37-43  n     "  43-55  M    '« 

anth.  cell,  15-17,1*    "  6-10  M     " 

Vera  Cruz,  Mexico. 

A  species  closely  resembling  this,  Oe.  scrobiculatitm  Wittr., 
has  been  described  from  Kquador  ;  the  dimensions  are  somewhat 
larger,  the  vegetative  cells  in  the  female  plant  ranging  from 
16-30  //. ;  the  oogonia  are  usually  solitary. 

26.  OE.  MARTINICENSE  Him,  1900,  p.  134,  PI.  XVI,  fig.  92  ; 
Oe.  crassum  Wolle,    1887,    p.   74,   PI.    LXXVI,   figs.    2   and   3. 
Monoecious  ;  oogonia  single,  oboviform  or  suboboviform,  pore 
superior;  oospore  oboviform  or  oboviform-ellipsoid,  almost  fill- 
ing the   oogonium,  membrane   smooth,   usually  rather  thick ; 
antheridia  i-5-celled,  hypogynous ;  spermatozoids  binate,  divi- 
sion vertical. 

veg.  cell,  33-37  yu  diam.,        3^-6^  diam.  long, 

oog.,  68-74  M    "  96-124  fj.  long, 

oos.,  66-72  M     "  81-96    M    " 

anth.  cell,  33-35  M    "  5-7      M     « 

Iowa,  Kansas,  Island  of  Martinique. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  241 

Resembles  Oe.  Landsboroughii ,  but  the  latter  is  dioecious. 

27.  OE.  LANDSBOROUGHII  (Hass.)  Wittrock,   1874,  p.   35; 
Wolle,    1887,  p.  91,  PI.  LXXXI,    figs.   8-n;    Him,    1900,  p. 
135,   PI.   XVI  and  XVII,  fig.  94;  P.  B.-A.,   No.  663.     Dioe- 
cious;   oogonia   single,  rarely    2,  oboviform   or  suboboviform, 
pore  superior;    oospore  oboviform  to  ellipsioid,    filling  or   not 
quite  filling  the  oogonium,  membrane  smooth  ;  male  plant  gen- 
erally a  little  more  slender  than  the  female  ;  antheridia  to  25- 
celled ;     spermatozoids     binate,     division    vertical ;    basal    cell 
elongate,    apical   cell   obtuse. 

veg.  cell,  female,      31-40  /Mcliam.,  3-6      diam.  long. 

veg.  cell,  male,          30-37  M     "  4-6         "         " 

oog.,  63-75  M     "  85-110  M  long. 

oos.,  59-yoM    "  73-102  M    " 

anth.  cell,  27-35  M     "  9-20    M    " 

Mass.,  Conn.,  N.  Y.,  Mexico.  Europe,  So.  'America. 

A  widely  distributed  species,  and  varying  somewhat,  but  not 
as  much  as  some  other  species  ;  a  form  has  been  found  in  Mex- 
ico with  veg.  cells  37-51  ft-  diam.,  otherwise  like  the  type.* 

28.  OE.  OBOVIFORME  Wittrock,   1878,  p.   140;  Him,   1900, 
p.   141,   PI.   XX,  fig.   103.     Dioecious;  oogonia  single,  obovi- 
form,   pore    superior;    oospore    oboviform,    about    filling    the 
oogonium,  rarely  ellipsoid-oboviform,  and  then  not  quite  filling 
the  oogonium,  membrane  smooth ;  male  plant  about  the  same 
size   as   the   female ;    antheridia    to    ig-celled ;    spermatozoids 
binate,  division  vertical ;  basal  cell  elongate. 

veg.  cell,  female,      21-33 /t  diam.,  3^-9      diam.  long, 

veg.  cell,  male,          21-31  n    "  3^-9        "          " 

oog.,  55-65  M     "  80-107  M  long, 

oos.,  54-6i  p.    "  70-85    M    " 

anth.  cell,    '  21-28  n    "  5-13    M     " 

Vera  Cruz,  Mexico.  So.  America. 

Quite  close  to  Oe.  grande,  but  distinguished  by  the  obovi- 
form oogonia. 

29.  OE.    PACHYANDRIUM  Wittrock  in  Wittr.   and  Nordst., 
Alg.  Exsicc.,  No.  5  ;    Wolle,  1887,  p.  89,  PI.  LXXV,   figs.  9 
and  10 ;  Hirn,    1900,  p.    142,  PI.    XX,    fig.    104.      Dioecious; 
oogonia   single   or  rarely   2,    very   rarely   3,   suboboviform   or 

*Wolle,  1887,  p.  92,  PI.  I,XXVI,  figs.  7  and  8,  describes  anew  var.  major 
of  Oe.  rivulare  (I<eCl.)  A.Br.;  Hirn,  1887,  p.  141,  thinks  that  this  may 
belong  under  Oe.  crassum,  forma  amplunt  (Magn.  &  Wille)  Hirn  ;  re- 
sembling Oe.  Landsboroughii,  but  of  larger  dimensions;  the  dimensions 
given  by  Wolle  are,  however,  larger  than  anything  recorded  for  any  form 
of  Oe.  crassum. 


242  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

oboviform-ellipsoid,  pore  superior ;  oospore  ellipsoid,  not  filling 
the  oogoniurn,  membrane  smooth  ;  male  plant  generally  some- 
what stouter  than  the  female;  antheridia  i-4-celled;  spermato- 
zoids  binate,  division  vertical. 

veg.  cell,  female,      30-36  M  diam.,  3-6/4  diaui.  long, 

veg.  cell,  male,          32-45  M     "  2-3/^     "          " 

oog.,  53-47  M     "  84-108  fji  long, 

oos.,  51-57  M     "  69-85    M     " 

antli.  cell,  3°-43  M     "  11-20    /u     " 

Pa.  and  N.  J.,  according  to  Wolle,  but  questioned  by  Him. 
The  species  so  much  resembles  forms  of  Oe.  grande  that  it  is 
quite  possible  that  Wolle's  plants  were  really  the  latter,  which 
occurs  at  a  number  of  American  stations. 

30.  OE.  GRANDE  Kiitzing,  1845,  P-  20° ;  Wolle,  1887,  p. 
95,  PL  L,XXVI,  fig  i  ;  Him,  1900,  p.  143,  PI.  XXI,  fig.  105  ; 
P.  B.-A.,  No.  811.  Dioecious;  oogouia  single,  rarely  2-5, 
slightly  swollen,  suboboviform,  pore  superior ;  oospore  same 
form  as  the  oogonium,  not  quite  filling  it,  membrane  smooth  ; 
male  plant  slightly  more  slender  than  the  female  ;  antheridia 
i-8-celled;  spermatozoids  binate,  division  vertical;  basal  cell 
elongate. 

veg.  cell,  female,      28-37  M  diam.,  2/4-5      diam.  long, 

veg.  cell,  male,          28-33  <"•     "  2^-5          "         " 

oog.,  49-60  n    "  86-100  M  long. 

COS.,  47-58  /*      "  64-93     M      " 

anth.  cell,  25-33  ^    "  11-18    M    " 

Ontario,  Me.,  Mass.,  Conn.,  Pa.,  Cal.  Europe,  Australia. 

A  species  of  varying  forms,  some  of  which  have  received 
names  in  Hirn's  monograph,  some  being  only  mentioned.,  with- 
out name.  Among  the  latter  is  the  form  from  Massachusetts, 
distributed  as  P.  B.-A.,  No.  519,  with  veg.  cells  4-11  diam. 
long,  oogonia  up  to  126  /u,  long,  oospores  to  104  /x,  the  diameter 
about  as  in  the  type ;  while  among  the  named  varieties  is 

Var.  ANGUSTUM  Him,  1900,  p.  146,  PI.  XXI,  fig.  no; 
P.  B.-A.,  No.  410.  Slender,  veg.  cells  and  oogonia  elongate, 
antheridia  to  36  cells,  oogonia  sometimes  4  in  succession. 

veg.  cell,  female,      19-30  M  diam.,          3^-n    diam.  long. 

veg.  cell,  male,          19-25  M     "  4-9          "         " 

oog.,  42-52  n    "  62-110  /j.  long. 

oos.,  40-50  fj.     "  60-89    <"•     " 

anth.  cell,  18-22  /j.    "  7-15    /u     " 

Mass.  So.  America. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  243 

Var.  AEQUATORIALE  forma  HORTENSE  Wittrock  in  Wittr. 
and  Nordst.,  Alg.  Exsicc.,  No.  1017;  Him,  1900,  p.  145,  PI. 
XXI,  fig.  109.  Smaller  than  the  type  in  all  parts,  oosporesless 
completely  filling  the  oogonium,  sometimes  globose-ellipsoid, 
and  then  not  nearly  filling  the  oogonium. 

veg.  cell,  female,      24-33  Mdiatn.,  2-4^  diam.  long, 

oog.,  42-51  fj.    "  63-88  /"long, 

oos.,  38-49  M    "  48-72  M    " 

These  measures  are  for  forma  hortcnsc ;  in  the  variety  the 
vegetative  cells  and  oogouia  are  proportionately  longer.  Green- 
land. Ecuador. 

31.  OE.  MEXICANUM  Wittrock,    1878,  p.    138;  Him,   1900, 
p.    147,   PI.  XXII,   fig.    in;  Tilden,  Amer.  Algae,   No.   257. 
Dioecious;    oogonia   single,    slightly  swollen,   cylindric-obovi- 
form,  pore  superior ;    oospore  of  the  same  form    as   the  oogo- 
nium, filling  or  nearly  filling  it,  membrane  smooth  ;  male  plant 
a  little  more  slender  than  the  female  ;  antheridia  to  8-celled  ; 
spermatozoids  binate,  division  vertical. 

veg.  cell,  female,      34-41  Mdiam.,  i&-3>£  diam.  long, 
veg.  cell,  male,         30-38  M    "  2-3 

oog.,  53-63  M    "  76-110  M  long, 

oos.,  51-60  M    "  63-80    M    " 

anth.  cell,  28-35  M    "  7-17    /*    " 

Mass.,  So.  Dakota,  Mexico. 

Nearly  related  to  Oe,  grande,  but  with  vegetative  cells  aver- 
aging larger  and  considerably  shorter,  oogouia  more  nearly 
cylindrical,  and  more  completely  filled  by  the  oospore. 

MACRANDRIA,  OPERCULATA,  GLOBOSPORA. 

32.  OE.  PUNCTATO-STRIATUM  De  Bary,  1854,  p.  47,  PI.  II, 
figs.  15  and  16;  Wolle,    1887,  p.  91,   PI.  LXXXV,  figs.  3-5  ; 
Him,  1900,  p.   152,  PI.  XXIII,  fig.   123;  Rabenhorst,  Algen, 
Nos.  214,  2276.    Diocecious;  oogonia  single,  depressed-globose, 
operculate,    division   median ;    oospore   depressed-globose,    not 
quite   filling   the   oogonium,    membrane   smooth  ;     male  plant 
slightly  more  slender  than  the  female  ;    antheridia  to  lo-celled, 
cells  slightly  swollen ;  spermatozoid  single ;  membrane  of  the 
vegetative  cells  and  oogonia  marked  with  spirally  placed  dot- 
like  pores ;    basal  cell  depressed-globose  or  subhemispherical, 
not  elongate,  membrane  vertically  plicate. 


244          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

veg.  cell,  female,      18-22  Mdiam.,  2-6    diam.  long. 

veg.  cell,  male,          16-19 /<.     "  2-6        "         " 

oog.,  48-55  n     "  38-48  M  long. 

dbs.,  40-51  M     "  35-43  M     " 

anth.  cell,  16-19  M     "  6-12  //,     " 

basal  cell,  28-31  /j.     "  21-25  n     " 

Greenland,  Florida.  Europe,  So.  America. 

Quite  distinct  from  other  American  species,  by  the  spiral 
markings  of  the  cell  walls,  as  well  as  by  other  characters.  The 
Florida  locality,  Wolle's  determination,  is  perhaps  doubtful. 

33.  OE.  HOWARDII  G.  S.West,  1904,  p.  281,  PI.  CCCCLXIV, 
figs.  1-5.     Dioecious;  oogonia  solitary,  globose  or  subglobose, 
operculate,  division  median  ;  oospore  globose  or  sub-depressed- 
globose,  filling  the  oogonium  ;  antheridia  pluricellular  ;    sper- 
matozoid  single  ;  vegetative  cells  slightly  but  distinctly  capitel- 
late ;  basal  cell  of  filament  subhemispherical  or  subspherical, 
not  elongate. 

veg.  cell,  female,     9. 5-11  M  diam.  2-4    diam  long. 

veg.  cell,  male,        7-5-9    M     "  2-4        "        " 

oog.,  29-33  M     "  29-33  M  long. 

oos.,  25-29  //,    "  25-29  n    " 

anth.  cell,  7.5-9    M     "  8-14/4    " 

basal  cell,  14-16/1     "  10-11 /x     " 

Barbados. 

With  basal  cell  similar  to  Oe.  pundato-striatum,  but  smaller 
in  all  dimensions,  and  without  the  spiral  markings  of  the  latter 
species. 

34.  OE.  PITHOPHORAE  Wittrock,  1878,  p.  141  ;  Him,  1900, 
p.  157,  PI.  XXIV,  fig.  134.     Monoecious ;  oogonia  single,  pyri- 
form-globose,   operculate,   division  superior;    oospore  globose, 
almost  filling  the  oogonium,  membrane  smooth,  often  thickish  ; 
antheridia  i  (or  more  ?)-celled,  subepigynous ;  basal  cell  elon- 
gate. 

veg.  cell,  9-11  M  diam.,  2^-4^  diam.  long, 

oog.,  26-30  M      "  27-35    /*  long. 

OOS.,  25-29  /x        "  24-29     fJ.        " 

anth.  cell,  8-10  /u      "  7-9      /x      " 

St.  Thomas,  W.  I.,  epiphytic  on  Pithophora  Cleveana. 

35.  OE.   CRISPUM   (Hass.)   Wittrock,    1874,   p.    10 ;    Wolle, 
1887,  p.  72,   PI.  LXXIV,  figs.   11-15;  Hirn,   1900,  p.  159,  PI. 
XXV,  fig.  138;  Wittr.   and   Nordst.,  Alg.  Exsicc.,  Nos.  209, 
508  ;  Tilden,  American  Algae,  No.  543.     Monoecious  ;  oogonia 
single,   very   rarely   2,    oboviform-globose,    operculate,    division 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  245 

superior ;  oospore  globose  or  subglobose,  almost  filling  the 
oogonium,  membrane  smooth;  antheridium  i-5-celled,  subepi- 
gynous  or  hypogynous  ;  spermatozoids  binate,  division  hori- 
zontal ;  basal  cell  elongate,  terminal  cell  obtuse. 

veg.  cell,  12-16  /u.  diam.,  3-4%  diam.  long. 

oog.,  37-45  M      "  41-53  n  long. 

oos.,  35-43  n      "  37-43  M     " 

anth.  cell,  8-14 /u.      "  7-12  M     " 

Greenland,  Pa.,  Vancouver,  Minn.,  Alaska,  Cal. 

Europe,  Asia,  Africa,  Australia,  So.  America, 
Perhaps  the  commonest  and  most  widely  distributed  species 
of  the  genus,  and   including  many  varieties  and  forms,  two  of 
which  occur  within  our  limits. 

Var.  GRACILESCENS  Wittrock  in  Wittr.  and  Nordst.,  Alg. 
Exsicc.,  No.  509  ;  Hirn,  1900,  p.  162,  PI.  XXV,  fig.  143  ;  P. 
B.-A.,  No.  518.  Slender,  oogonia  and  oospores  varying  in 
form,  oogonia  oboviform-globose  to  oboviform-pyriform  or  sub- 
ellipsoid,  generally  single,  rarely  2  or  3  ;  oospores  globose  to 
ellipsoid. 

veg.  cell,  10-14  M  diam.,  3-5    diam.  long. 

oog.,  33-39 /*      "  33-5 1  M  long. 

oos.,  32-37  M      "  33-42  n    " 

anth.  cell,  9-10  /u      "  7-9    ^    " 

Mass.,  Minn.,  (Pa.?),  Mo.  So.  America. 

The  Pa.  locality  is  surmised  from  Wolle's  figure,  which  may 
represent  this  variety,  though  given  as  Oe.  vernale  (Hass.) 
Wittr. 

Var.  URUGUAYENSE  Magnus  and  Wille  in  Wille,  1884,  p. 
39,  PI.  II,  fig.  63;  Hirn,  1900,  p.  164,  PI.  XXVI,  fig.  145; 
Wittr.  and  Nordst.,  Alg.  Exsicc.,  No.  311,  as  Oe.  crispum  f. 
typicum.  Smaller,  veg.  cells  shorter,  oogonia  single,  subobovi- 
form-globose  ;  oospore  filling  the  oogonium  ;  antheridia  subepi- 
gynous,  hypogynous  or  sometimes  scattered. 

veg.  cell,  10-14  /"•  diam.,  iK'3^2  diam.  long. 

oog.,  30-38  p      "  33-43    Mlong. 

oos.,  27-35  /*      "  27-37    M     ' 

anth.  cell,  8-13  /*      "  6-12    M    ' 

pa.  So.  America. 

36.  OE.  OBESUM  (Wittr.)  Hirn,  1900,  p.  166,  PI.  XXVI, 
fig.  148.  Monoecious;  oogonia  single,  oboviform-globose,  oper- 
culate.  division  superior ;  oospore  globose,  not  quite  filling  the 
oogonium,  membrane  smooth,  often  thickened  ;  antheridia  i-2>- 


246  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

celled,  subepigynous  or  more  rarely  subhypogynous  ;  spermato- 
zoids  binate,  division  horizontal. 

veg.  cell,  12-15  /u  diam.,  2/^5    diam.  long. 

oog.,  40-43  p.      "  38-44  /x  long. 

oos.,  33-35  M      "  33-35  /*     " 

anth.  cell,  11-14  M      "  10-15/01     " 

Mass.  Europe. 

Resembles  Oe.  crispum,  but  the  oospores  are  smaller  in  pro- 
portion to  the  oogonia,  and  the  oogonia  are  always  solitary  ; 
from  Oe.  autumnale  it  is  distinguished  by  the  smaller  but  longer 
vegetative  cells. 

37.  OE.  AUTUMNALE  Wittrock,  1874,  p.  n  ;  Wolle,  1887,  p. 
73,  PI.  LXXXI,  figs.  1-5;   Him,   1900,  p.  167,  PI.  XXVI,  fig. 
151.     Monoecious  ;  oogonia  single,  oboviform-globose,  opercu- 
late,  division  superior  ;  oospore  globose  or  subglobose,  filling  or 
nearly  filling  the  oogonium,  membrane  smooth  ;  antheridia  1-2- 
celled,  subepigynous,  hypogynous  or  scattered  ;    spermatozoids 
binate,  division  horizontal ;    basal   cell  elongate,  terminal  cell 
shortly  acute. 

veg.  cell,  16-20  M  diam.,  1/^-2,^  diam.  long. 

oog.,  39-45  M      "  45-51    M  long. 

oos.,  37-42  M      "  37-44    M     " 

anth.  cell,  15-18  M      "  9-10    /j.    " 

Pa.  Europe. 

Not  far  from  Oe.  crispum,  but  with  stouter  and  shorter  vege- 
tative cells,  and  relatively  less  swollen  oogonia.  Its  occurrence 
in  America  has  no  other  proof  than  the  reference  in  Wolle. 

38.  OE.  PRINGSHEIMII  Cramer,  1859,  p.  17,  PL  I,  figs.  1-4; 
Wolle,  1887,  p.  90,  PI.  LXXXII,  figs.  4-6;  Him,  1900,  p.  170, 
PI.    XXVII,   fig.    155 ;    Rabenhorst,   Algen,    No.    790.     Dioe- 
cious ;     oogonia    2-6-seriate   or    single,    suboboviform-globose, 
operculate,   division    superior ;    oospore    globose,   almost  filling 
the  oogonium,  membrane  smooth,  thickish  ;  male  plant  slightly 
more  slender  than  the  female  ;  antheridia  to  lo-celled,  always 
alternating  with  vegetative  cells  ;  spermatozoids  binate,   divi- 
sion horizontal  ;    basal   cell  elongate,  terminal  cell   obtuse   or 
short-apiculate. 

veg.  cell,  female,       14-20  /JL  diam.,  2-5    diam.  long, 

veg.  cell,  male,          12-16  fj.      "  2-4        "         " 

oog.,  35-43  n     "  36-46  M  long, 

oos.,  30-37  M      "  3°-37  M     " 

anth.  cell,  11-15  n     "  6-9    M     " 

N.  Y.,  Pa.,  Florida.  Europe,  Africa,  Australia. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  247 

A  widely  distributed  species,  but  the  occurrence  with  us  of 
the  typical  form  is  recorded  only  by  Wolle,  who  does  not  men- 
tion var.  Nordstedtiii  which  certainly  does  occur  here  ;  possibly 
his  plants  belong  rather  to  the  variety. 

Var.  NORDSTEDTII  Wittrock  in  Wittr.  and  Nordst.,  Alg. 
Exsicc.,  Nos.  8  and  205;  Him,  1900,  p.  171,  PI.  XXVII,  fig. 
156.  Smaller,  oogonia  single,  rarely  2,  oboviform-globose, 
oospore  not  quite  filling  the  oogouiuui. 

veg.  cell,  female,       10-16 /u  diam.,  2-4^  diatn.  long. 

veg.  cell,  male,  9-15  M      "  2-4%      "         " 

oog.,  28-39 /x      "  36-45    Mcmg. 

oos.,  26-34  n      "  27-34    M     " 

anth.  cell,  9-12  /u      "  ,8-9      /u     " 

Greenland,  Minnesota,  Cal.  Europe,  Asia. 

MACRANDRIA,  OPERCULATA,  ELLIPSOSPORA. 

39.  OE.  AHLSTRANDII  Wittrock  in  Wittr.  and  Nordst.,  Alg. 
Exsicc.,    No.   401  ;  Him,    1900,  p.    183,    PI.   XXIX,  fig.    179. 
Monoecious;  oogonia  ellipsoid,  single,  operculate,  division  su- 
perior ;    oospore    ellipsoid,    filling    the    oogonium,    membrane 
smooth ;    antheridium   i-2-celled,   hypogynous ;    spermatozoids 
binate,  division  horizontal ;  terminal  cell  obtuse. 

veg.  cell,  10-18  M  diatn.,  3-10  diam.  long, 

oog.,  34-42  M    "  57-69  /*  long, 

oos.,  34-41  M    "  53-62  n    " 

anth.  cell,  13-17  M    "  9'12  M    " 

N.  Y.  Sweden. 

40.  OE.   GRACIIXIMUM  Wittrock  and    Lund    in  Wittrock, 
1874,  p.  15  ;  Wolle,  1887,  p.  74,  PI.  LXXV,  fig.  2  ;  Hirn,  1900, 
p.   184,    PI.    XXIX,    fig.    1 80.     Monoecious;    oogonia   single, 
oblong,  operculate,  division  superior ;  oospore  oblong-ellipsoid, 
not  filling  the  oogonium,  membrane  smooth  ;  antheridia  subepi- 
gynous,  hypogynous  or  subhypogynous,  unicellular  ;  spermato- 
zoids binate,  division  horizontal. 

veg.  cell,  3^-7    Mdiam.,  4/^-6    diam.  long. 

'    oog.,  14-19  M     "  34-40  M  long, 

oos.,  13-17  M     "  24-32  M 

anth.  cell,  3'5    *      "  47    M 

pa  Europe. 

41.  OE.  NODULOSUM  Wittrock,  1872,  p.  22,  PI.  I,  figs.  8-10; 
Him,  1900,  p.  187,  PI.  XXIX,  fig.  184.     Monoecious;  oogonia 
single  or  2,  oboviform-globose,  more  rarely  oboviform-ellipsoid, 
operculate,  division  superior;    oospore   globose  or  subglobose, 
more  rarely  globose-ellipsoid,  almost  filling  the  oogonium,  mem- 


248  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

brane  smooth,  often  thick;  antheridia  i-3-celled,  subepigynous 
or  hypogynous ;  spermatozoids  binate,  division  horizontal ; 
vegetative  cells  with  two  undulate  constrictions ;  basal  cell 
elongate,  not  constricted  ;  terminal  cell  obtuse  or  apiculate. 

veg.  cell,  20-29  P  diatn.,  i}4-4/4  diam.  long. 

oog.,  48-57  /x    "  56-73    Mong. 

oos.,  46-53  /*     "  49-56    M     " 

anth.  cell,  18-25  f-     "  7-9      M     " 

The  type  occurs  in  Europe,  Asia,  Australia,  and  So.  America, 
but  has  not  been  reported  from  No.  America  ;  but  we  have 

Var.  COMMUNE  Him,  1900,  p.  187,  PI.  XXX,  fig.  185;  P. 
B.-A.,  No.  74,  as  Oe.  nodulosum.  Oogonia  and  oospores  larger, 
the  former  suboboviform-ellipsoid  to  ellipsoid,  more  rarely 
globose-ellipsoid . 

veg.  cell,  22-29  M  diam.,  i>^-4K  diam.  long. 

oog.,  64-74  n     "  70-90    M  long. 

oos.,  56-70  M     "  67-80    /j.    " 

anth.  cell,  18-26  M    "  7-10    n    " 

Mass.  Finland. 

The  specific  name  is  due  to  the  constrictions  in  the  vegetative 
cells,  each  cell  appearing  to  consist  of  three  parts,  separated  by 
necks.  No  other  American  species  has  this  character. 

42.  OE.  NOBILE  Wittrock,  1874,  p.  14;  Hirn,  1900,  p.  189, 
PI.  XXX,  fig.  188.  Monoecious ;  oogonia  single,  very  rarely 
2,  ellipsoid  or  suboboviform-ellipsoid,  operculate,  division 
superior;  oospore  ellipsoid-globose  or  globose,  not  filling  the 
oogonium,  membrane  triple  ;  outer  membrane  smooth,  median 
membrane  with  30-35  continuous  longitudinal  lines,  rarely  anas- 
tomosing, inner  membrane  smooth  ;  antheridia  i-3-celled,  hypo- 
gynous ;  spermatozoids  binate,  division  horizontal.  • 

veg.  cell,  16-20  M  diam.,  5-9    diam.  long. 

oog.,  57-65  M     "  67-90  n  long. 

oos.,  48-55  M     "  67-79  M     " 

anth.  cell,  18-19  M    "  9-13  n    " 

The  dimensions  given  are  of  the  type  occurring  in  Norway  ; 
the  American  form,  occurring  in  Mass.,  has  dimensions  as 
follows :  — 

veg.  cell,  14-20  M  diam.,  6-u  diam.  long. 

oog.,  57-63  M    "  81-95  /u  long. 

oos.,  55-6o  M    "  67-79  v-    " 

anth.  cell,  14-19  M     "  13-17  M     " 

As  the  characters  otherwise  agree,  the  form  does  not  seem  to 
require  a  special  name.  This  species  has  the  spore  membrane 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  249 

similar  to  that  of  Oe.  Boscii,  but  is  distinguished  by  the  opercu- 
late  oogonium,  as  well  as  by  other  characters. 

NANNANDRIA,  ANTHERIDIUM   EXTERIUS,  PORIFERA, 
GLOBOSPORA. 

43.  OE.  BRAUNII  Kiitzing,  1849^.366;  Wolle,  1887,  p.  79, 
PI.  LXXIX,  figs.  6  and  7;  Him,   1900,   p.    194,   PI.    XXXII, 
fig.  197;  Wittr.  and  Nordst.,  Alg.  Exsicc.,  No.  15.    Dioecious, 
nanuaudrous,    gynandrosporous ;    oogonia   single,   ellipsoid   or 
subglobose,  pore  median  ;  oospore  globose,  not  quite  filling  the 
oogonium,  membrane  smooth  ;    suffultory  cell   slightly  or  not 
swollen  ;    androsporangia   i-2-celled  ;    basal  cell  elongate,  ter- 
minal cell  obtuse  ;  dwarf  males  near  the  oogonia,  often  on  the 
suffultory  cell,  stipe  sometimes  5-celled,  antheridium  external, 
unicellular,  stipe  slightly  curved. 

veg.  cell,  13-15  M  diatn.,  2-4     diam.  long, 

suf.  cell,  16-20  M  "  i%-2%      "        " 

oog.,  30-37  /j.  "  33-43 /a  long, 

oos.,  27-33  M  "  27-33  M     " 

andr.  cell,  13-15  /"•  "  11-12  /j.     " 

nan.  stipe,  7-12  /u  "  20-28  M     " 

anth.  cell,  5-8    AC  "  9-10 /u     " 

N.  J.,  Pa.  Europe,  Africa. 

44.  OE.  FLAVESCENS  (Hass.)  Wittrock,    1870,  p.   127,  PI. 
LIII,  fig.  9;  Wolle,  1887,  p.   78,  PI.  IvXXVIII,  figs,  i  and  2; 
Hirn,   1900,  p.   196,  PL  XXXII,  fig.  199.     Dioecious,  nannan- 
drous,  idio-   or  gynandrosporous ;  oogonia  single,  ellipsoid  or 
subglobose    (sometimes  sub-hexagonal-globose),  pore  median  ; 
oospore   globose,    not   quite   filling   the   oogonium,   membrane 
smooth ;  suffultory  cell  similar  to  other  veg.  cells ;  androspor- 
angia i-9-celled  ;•  dwarf  males  slightly  curved,  on  the  suffultory 
cell,  autheridium  external,  i-  (or  2-)  celled. 

veg.  cell,  18-23  M  diarn.,  4-6    diam.  long. 

oog.,  49-52 /"•    "  51-60  M  long. 

oos.,  45-49  /*    "  45-49  v-    ' 

andr.  cell,  17-20  M     "  8-18  M     ' 

nan.  stipe,  11-12  /x    "  36-45  M 

anth.  cell,  9-10  M    "  15-20  M     " 

Mass.,  Minn.  Sweden. 

'Somewhat  like  the  preceding  species  in  character,  but  of 
larger  dimensions ;  the  oogonium  is  often  of  hexagonal  form 
when  young,  later  becoming  globose. 

45.  OE.  PUNGENS  Hirn,  1900,  p.  199,  PL  XXXII,  fig.  203. 


250          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Dioecious,  nannandrous,  gynandrosporous ;  oogonia  single,  de- 
pressed-globose or  subglobose,  pore  median  or  slightly  higher; 
oospore  subglobose,  nearly  filling  the  oogonium,  epispore  cov- 
ered with  subuliform  spines ;  suffultory  cell  similar  to  other 
veg.  cells;  androsporangia  hypogynous,  i-  (or  more-?)  celled; 
dwarf  males  slightly  curved,  on  the  suffultory  cells,  antheridium 
external,  i-2-celled. 


veg.  cell, 
oog., 

COS., 

andr.  cell, 

12-16  /u  diam., 
40-48  M      '  ' 

37-44  M     " 

14-16  yu      " 

4-6    diam.  long. 
40-50  fj.  long. 
35-43^     " 

IO-I5  M      " 

nan.  stipe, 
anth.  cell, 

9-12  fJ.      " 

6-7    M     " 

20-30  /u      '  ' 
8-12  M      " 

So.  Carolina. 

This  species  was  collected  by  Ravenel,  but  the  specimen  re- 
mained unnoticed  until  Hirn  found  it  and  published  it  in  his 
Monograph  in  1900.  It  is  quite  similar  in  character  to  Oe. 
aster,  a  Swedish  plant,  also  of  a  single  station,  which  has  a 
similar  spinous  oospore,  but  is  smaller  in  all  its  dimensions, 
with  longer  cells  ;  Oe.  cchinospcrmum  has  similar  spines  on  the 
oospore,  but  has  stouter  vegetative  cells,  so  that  the  oogonia  do 
not  appear  so  swollen ;  they  are  moreover  ellipsoid  instead  of 
depressed. 

46.  OE.  ECHINOSPERMUM  A.  Braun  in  Kiitzing,  1849,  p. 
366;  Wolle,  1887,  p.  86,  PI.  LXXXIV,  fig.  7;  Hirn,  1900,  p. 
199,  PI.  XXXIII,  fig.  204;  Wittr.  and  Nordst.,  Alg.  Exsicc., 
Nos.  12,  506.  Dioecious,  nannandrous,  gynandro- or  idioandro- 
sporous ;  oogonia  single,  ellipsoid-globose  or  subglobose,  pore 
median  ;  oospore  globose,  almost  filling  the  oogonium,  epispore 
with  subulate  spines  ;  suffultory  cell  not  swollen  ;  androspor- 
angia i-5-celled,  dwarf  males  slightly  curved,  on  the  suffultory 
cell,  antheridium  external,  i-2-celled. 

veg.  cell,  18-30  M  diam.,          2%-$l/2  diam.  long. 

oog.,  39-50  M     "  41-57    Mlong. 

COS.,  38-47  M      "  38-49     M      " 

andr.  cell,  21-25  M     "  9-I5    M     " 

nan.  stipe,  10-15  M     "  26-35    M     " 

anth.  cell,  6-12  fj.    "  6-15    /a     " 

Mass.,  N.  Y.,  N.  J.,  Pa.  Europe. 

Var.  HORRIDUM  Hirn,  1900,  p.  201,  PI.  XXXIII,  fig.  205; 
Oe.  echinospermum  var.  ?  Wolle,  1887,  p.  86,  PL  L,XXXV, 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  251 

figs.  6-9.  Larger,  spines  of  the  oospore  longer  and  denser ; 
antheridium  pluricellular. 

Florida. 

The  distinctions  between  Oc.  echinospernium  and  Oe.  pungcns 
were  given  under  the  latter  species  ;  the  var.  horridum  has 
quite  a  different  appearance  from  the  type,  and  when  better 
known  may  prove  to  be  a  distinct  species. 

47.  OE.  IRREGULARS  Wittrock,  1870,  p.  128;  Wolle,   1887, 
p.  79,  PI.  LXXVIII,  figs.   4  and  5  ;  Hirn,    1900,  p.  202,  PI. 
XXXIII,  fig.   207.     Dioecious,   nannandrous ;  oogonia  single, 
globose  or  subdepressed-globose,  pore  superior  ;  oospore  globose, 
filling   the  oogonium,  membrane  smooth ;    suffultory    cell    not 
swollen  ;  dwarf  males  straight,  near  or  on  the  oogonium  ;  an- 
theridium exterior,  i-4-celled. 

veg.  cell,  15-20  p.  diam.,  2^-4    diaru.  long, 

oog.,  37-45- /*    "  36-47  M  long. 

COS.,  36-42  M      "  34-41  ft      ' 

nau.  stipe,  12-15  n    "  20-24  M     " 

anth.  cell,  10-12  ju,     "  6-8    n    " 

Florida.  Northern  Europe. 

This  species  is  in  habit  much  like  the  monoecious  Oe.  fragile  ; 
the  globose  oogonia  often  occur  throughout  a  long  vegetative 
filament,  with  only  one  or  two  vegetative  cells  between  ;  the 
short  dwarf  males  are  usually  at  right  angles  to  the  filament. 

48.  OE.  ARMIGERUM  Hirn,  1900,  p.  203,  PI.  XXXIII,  fig. 
208.       Dioecious,    nannandrous ;    oogonia   single,    subglobose, 
pore  superior  ;  oospore  globose,  almost  filling  the  oogonium  ; 
epispore  with  subulate  spines ;    suffultory  cell  similar  to  other 
veg.  cells ;  dwarf  males  curved,  on  the  suffultory  cell,  stipe  not 
seldom  2-4-celled  ;  antheridium  exterior  i-  (or  more-?)  celled. 

veg.  cell,  9-11  /ttdiam.,  4-10  diam.  long, 

oog.,  29-33  /t     "  32-35  p  long, 

oos.,  26-29  M     "  26-29  <"•     " 

lower  cell,  nan.  stipe,  7-8    M    "  20-24  M 

upper  cell,  nan.  stipe,  4.5-6    M    "  21-30  M 

anth.  cell,  5'6    M    "  7-8    /*     " 

So.  America. 

This  species  and  the  following,  Oe.  echinatum,  are  notably 
smaller  than  our  other  species  with  spinous  spores  ;  Oe.  echina- 
tum is  larger  than  Oe.  armigerum,  with  more  spherical  oogonia 
and  oospores ;  the  spines  are,  moreover,  rather  conical  than 
aculeate.  The  only  reason  for  including  Oe.  armigerum  here  is 


252  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

that  the  figures  given  by  Wolle  for  Oe.  echinatum  seem  to  Hirn 
to  be  more  like  Oe.  armigerum,  which  was  undescribed  at  the 
time  Wolle's  book  was  published,  than  like  Oe.  echinatum. 
They  are  much  more  complete  than  Wood's  figures,  but  Wolle 
does  not  give  the  locality  of  the  plant  from  which  they  were 
made. 

49.  OE.  ECHINATUM  (Wood)  Wittrock,  iSySa,  p.  137  ;  Hirn, 
1900,    p.   204;   Androgynia   cchinata    Wood,    1872,    p.    198,    PI. 
XVIII,  fig.  3.     Dioecious,  nannandrous ;  oogonia  single,  glo- 
bose, usually  depressed,   pore  superior;  oospore  same  form  as 
the  oogonium,  nearly  filling  it,  epispore  with  narrowly  conical 
spines ;  dwarf  males  nearly  straight,  near  the  oogonia. 

veg.  cell,  8-12  M  diam.,  6-14  diam.  long. 

OOg.,  35-36  fJ.        " 

oos.,  25-26,11      "  25-26  fj.  long. 

Pa. 

A  quite  imperfectly  known  species ;  see  notes  under  Oe. 
armigerum . 

50.  OE.  STELLATUM  Wittrock,    1870,  p.    129  ;   Wolle,  1887, 
p.  85,  PI.   LXXXIV,   figs,    i   and  2;  Him,    1900,  p.  205,  PI. 
XXXIV,  fig.  210.     Dioecious,  nannandrous,  gynandrosporous  ; 
oogonia  single  or  2-3,  oboviform-globose,  pore  superior  ;  oospore 
globose,    about    filling   the   oogouium,    epispore   with    conical 
spines,  arranged  in  4-7  occasionally  anastomosing  spirals,  sufful- 
tory  cell  hardly  swollen  ;  androsporangia  i-3-celled,  generally 
subepigynous ;  basal  cell  elongate,  terminal  cell  slender,  hya- 
line,  obtuse ;  dwarf   males   nearly  straight,   on   the   suffultory 
cells,  antheridium  exterior,  i-2-celled. 

veg.  cell,  15-35 /x  diam.,  3-6    diain.  long. 

oog.,  51-64  fj.      '  56-70  /u  long. 

oos.,  50-58  /j.      '  50-58  M     " 

andr.  cell,  14-19  M      '  13-20/4     " 

nan.  stipe,  11-13  M      '  45-52  M     " 

antli.  cell,  6-9    /u      '  8-13  /u.     " 

Florida.  Europe,  Africa,  Australia,  So.  America. 

From  the  previously  noted  species  with  spinous  spores  this  is 
distinguished  by  the  spiral  arrangement  of  the  spines,  which 
are  also  stouter  and  relatively  shorter  than  in  the  species  before 
mentioned .  These  characters  it  shares  with  Oe.  Donnellii,  which 
is,  however,  a  larger  plant  in  every  way.  The  great  variation 
in  the  diameter  of  the  vegetative  cells  in  the  same  filament  is  a 
noticeable  character  of  this  species. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  253 

51.  OE.   DONNELLII  Wolle,  1880,  p.  48;  1887,  p.   85,  PI. 
LXXXIV,  figs.  3-6;  Him,  1900,  p.  206,  PI.  XXXIV,  fig.  211. 
Dioecious,    naunandrous,    idioandrosporous ;    oogonia    single, 
rarely  double,  slightly  swollen,  oboviform-globose,  pore  supe- 
rior ;    oospore  globose,  not  fully  filling  the  oogonium  ;   epispore 
with  conical  spines,  arranged  in  5-7  occasionally  anastomosing 
spirals  ;  suffultory  cell  not  swollen  ;  androsporangia  4-io-celled  ; 
dwarf  males  slightly  curved,  on  the  suffultory  cell,  rarely  on  the 
oogonium  ;  antheridium  exterior,  i-2-celled. 

veg.  cell,  41-59  M  diam.,  J/i'3    diain.  long. 

oog.,  63-78  fj.      "  70-93 /u  long. 

oos.,  60-70/01      "  60-70  M     " 

andr.  cell,  40-45  yu.      "  10-12  M     " 

nan.  stipe,  16-21  M      "  63-74  ^     ' 

anth.  cell,  14-15  M      "  8-22  /u     " 

Florida. 

Hirn's  examination  of  authentic  specimens  enabled  him  to 
correct  and  complete  the  descriptions  and  figures  of  Wolle. 

52.  OE.  HUNTII  Wood,    1869,  p.    333 ;    1872,    p.    198,   PI. 
XVII,  fig.  2;  Wolle,  1887,  p.  85,  PI.  LXXXIV,  fig.  9;  Him, 
1900,  p.  208,  PL  XXXIV,  fig.  213;  P.  B.-A.,No.  1471.     Dioe- 
cious, nannandrous ;  oogonia  single,   subglobose  or  subobovi- 
form-globose,  pore   inferior ;    oospore   globose,   not   filling   the 
oogonium,  epispore  with  four  raised  spiral  lines  ;  suffultory  cell 
similar  to  other  vegetative  cells ;  basal  cell  elongate,  terminal 
cell  tapering,  produced  into  a  long  hyaline  seta  ;  dwarf  males 
nearly  straight,  on  the  suffultory  cells  ;  antheridium  exterior,  i- 
(or  2-?)  celled. 

veg.  cell,  15-25  M  diam.,  2^-3^  diam.  long. 

oog.,  50-60  M      "  52-6o    /"long. 

oos.,  38-42  M      "  38-42    /i    ' 

nan.  stipe,  n  M      "  52    M     ' 

anth.  cell,  10  M      "  3°    f*     ' 

Mass.,  Pa. 

Wood's  record  was  long  the  only  one  for  this  species,  which 
he  found  growing  in  his  aquarium.  Wolle  merely  condenses 
Wood's  description,  and  Him  copies  it,  and  gives  dimensions 
taken  from  Wood's  figures.  Its  nearest  relative  seems  to  be  Oe. 
spirale  from  Java,  but  in  the  latter  the  arrangement  of  the 
spirals  is  quite  different.  For  occurrence  in  Mass.,  see  Collins, 
igoSb,  p.  57. 

53.  OE.   SEXANGULARE  Cleve  in  Wittrock,    1870,  p.    131  ; 
Wolle,  1887,  p.  82,  PI.  LXXIX,  figs.  8  and  9 ;  Him,  1900,  p. 


254          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

211,  PI.  XXXV,  fig.  216;  Wittr.  and  Nordst.,  Alg.  Exsicc., 
No.  12.  Dioecious,  nannaudrous,  gynandrosporous ;  oogonia 
single,  rarely  double,  sexangular-ellipsoidal,  having  the  great- 
est width  and  the  pore  slightly  above  the  middle  ;  oospore  same 
form  as  the  oogonium,  quite  filling  it,  membrane  smooth ; 
suffultory  cell  not  or  slightly  swollen ;  androsporangia  1-3- 
celled,  dwarf  males  on  suffultory  cells,  slightly  curved ;  stipe 
sometimes  2-3-celled  ;  antheridium  exterior,  unicellular. 

veg.  cell,  9-16  /j-  diam.,  3-7    diam.  long. 

oog.,  .       29-33  M     "  33-39  M  long. 

COS.,  27-31  fJ.      "  31-36  M      " 

andr.  cell,  13-14  M     "  10-14  M     " 

nan.  stipe,  7-9    M     "  21-30  M     " 

anth.  cell,  6-7    M     "  9-12  n     " 

Pa.  Europe. 

Var.  MAJUS  Wille,  1880,  p.  68;  Him,  1900,  p.  212,  PL 
XXXV,  fig.  217;  P.  B.-A.,  No.  522.  Larger,  oogonia  most 
swollen  at  the  middle,  pore  median. 

veg.  cell,  15-23 /i  diam.,  2-3    diam.  long. 

oog.,  36-42  /a     "  41-45  /j.  long. 

oos.,  34-40  M     "  39-43  /j.     " 

andr.  cell,  14-18 /i     "  8-10 /u    " 

nan.  stipe,  7-9    /u     "  18-30  M     " 

anth.  cell,  6-8    M     "  6.5-10  M     " 

Mass.  Europe. 

The  form  of  the  oogonium  easily  distinguishes  this  from  all 
other  species,  American  or  foreign. 

54.  OE.  HYSTRIX  Wittrock,  1870,  p.  133  ;  Wolle,  1887,  p. 
87,  PI.  LXXXIV,  fig.  8;  Him,  1900,  p.  213,  PI.  XXXV,  fig. 
218.  Dioecious,  nannandrous,  gyuandrosporous  (or  possibly 
idioandrosporous) ;  oogonia  single,  ellipsoid,  pore  median; 
oospore  ellipsoid,  nearly  filling  the  oogonium,  covered  with  sub- 
ulate spines ;  suffultory  cell  little  or  not  swollen ;  androspor- 
angia i-3-celled,  terminal  cell  obtuse ;  dwarf  males  slightly 
curved,  on  the  suffultory  cell ;  antheridium  exterior,  unicellular. 

veg.  cell,  17-28  /JL  diam.,  i%-4>2  diam.  long. 

oog.,  38-48  fj.    "  45-65    n  long. 

oos.,  37-46  M    "  43-55    n    " 

andr.  cell,  17-18  /x     "  13-18    /u     " 

nan.  stipe,  10-11  M    "  22-25    M     " 

anth.  cell,  6-8    /x     "  9-14    /«     " 

Pa.  Europe. 

Distinguished  from  all  other  spinous  species  by  the  elongate 
spines  and  the  very  short  dwarf  males. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA 


255 


55.  OE.  CRASSIUSCULUM  var.  IDIOANDROSPORUM  Wittr.  and 
Nordst.,  Alg.  Exsicc.,  Nos.  208,  310;  Wolle,  1887,  p.  80,  PI. 
LXXVII,  figs.  14-19;  Him,  1900,  p.  215,  PI.  XXXV,  fig. 
220;  P.  B.-A.,  Nos.  72,  716.  Dioecious,  nannandrous,  idioan- 
drosporous  ;  oogonia  single  or  2,  globose-oboviform  to  globose  ; 
oogonia  ellipsoid-globose  to  angular-oboviform  or  angular-glo- 
bose, nearly  filling  the  oogonium  ;  pore  superior  ;  membrane 
smooth,  thick  ;  suffultory  cell  similar  to  the  other  vegetative 
cells:  androsporangia  2-5-celled  ;  dwarf  males  nearly  straight, 
on  or  near  the  suffultory  cell;  antheridium  exterior,  i-  (or 
more-  ?)  celled. 


veg.  cell, 
oog., 
oos., 

andr.  cell, 
nan.  stipe, 
anth.  cell, 


25-36  /u  diam., 

48-59  /"•  " 

42-57  /a  " 

30-34  ju.  " 

14-16  fj.  " 

8-10  /x  " 


2^-5  #  diam.  long. 
57-90    M  long. 
50-66    n    " 
12-21    M     " 
60-70    M     " 
10-18    M     " 


Me.,  Mass.,  Conn.,  N.  Y.,  N.  J.,  Pa.,  Minn.,  So.  Dakota. 

Northern  Europe. 

The  type,  occurring  in  northern  Europe,  is  gynandrosporous, 
and  never  has  the  angular  oospores.  The  plants  from  Maine 
and  Mass.,  distributed  under  No.  72,  P.  B.-A.,  have  the 
oospores  and  oogonia  broader  and  more  globose,  often  4  in  a 
series  ;  the  androsporangia  are  more  slender.  From  the  three 
following  species,  resembling  it  in  many  particulars,  Oe.  crassi- 
iisculum  in  all  its  forms  can  be  distinguished  by  the  unswollen 
suffultory  cell  ;  the  unusually  thick  membrane  is  also  to  be 
noted. 

56.  OE.  BORISIANUM  (Le  Cl.)  Wittrock,  1870,  p.  132; 
Wolle,  1887,  p.  81,  PI.  LXXVIII,  figs.  6-9;  Him,  1900,  p. 
217,  PL  XXXVI,  fig.  223;  P.  B.-A.,  No.  517.  Dioecious, 
nannandrous,  gynandrosporous  or  idioandrosporous  ;  oogonia 
single,  or  rarely  2-3,  oboviform  or  quadrangular-ellipsoid,  pore 
superior;  oospore  ellipsoid  or  oboviform,  sometimes  quadrangu- 
lar-ellipsoid, not  quite  filling  the  oogonium,  membrane  smooth  ; 
suffultory  cell  swollen  ;  androsporangia  i-7-celled,  in  the  upper 
part  of  the  filament,  often  subepigynous  ;  basal  cell  elongate  ; 
terminal  cell,  which  may  be  an  oogonium,  short-apiculate  or 
obtuse,  or  sometimes  produced  in  a  long,  hyaline  seta  ;  dwarf 
males  slightly  curved,  on  suffultory  cell  ;  antheridium  exterior, 
i-2-celled. 


256          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

veg.  cell,  15-23  M  diam.,  3-6      diam.  long. 

suf.  cell,  31-38  /u    "  i^-2>^     "        " 

oog.,  40-50  M     "  55-9°    /"long. 

oos.,  35-46  fj.    "  48-60   n    " 

andr.  cell,  16-19  M     "  15-23    M     " 

nan.  stipe,  12-15  M     "  35'47    M     " 

anth.  cell,  7-10  M    "  11-15    ^     " 

Mass.,  Pa.,  Cal.  Europe,  Australia,  So.  America. 

A  common  species,  distinguished  from  Oe.  crassinsculum  by 
the  much  swollen  cell  below  the  oogonium ;  the  cells  are  rela- 
tively slender  just  above  the  oogonium,  and  increase  rapidly 
and  uniformly  to  and  including  the  oogonium  ;  above  this  the 
cell  is  slender  again  ;  from  the  two  following  species,  Oe.  Wolle- 
anum  and  Oe.  concatenation,  it  is  distinguished  by  the  oospore 
being  smooth,  not  striate. 

57.  OE.  WOLLEANUM  Wittrock,  i878a,  p.  137  ;  Wolle,  1887, 
p.  82,  PI.  L,XXX,  figs.  4  and  5;  Him,  1900,  p.  220,  PI. 
XXXVII,  fig.  226;  Wittr.  and  Nordst.,  Alg.  Exsicc.,  No.  107. 
Dioecious,  nannandrous,  gynandrosporous  or  idioandrosporous  ; 
oogonia  single  or  2,  more  rarely  3-4,  suboboviform  or  quadran- 
gular-ellipsoid, pore  superior,  membrane  with  raised  longitud- 
inal lines  on  the  inner  surface  ;  oospore  same  form  as  the  oogo- 
nium, quite  filling  it,  membrane  double ;  external  membrane 
with  25-35  longitudinal  raised  lines,  rarely  anastomosing ;  inner 
membrane  smooth  ;  suffultory  cell  swollen  ;  androsporangia  1-3- 
celled,  often  subepfgynous,  or  scattered  in  the  upper  part  of  the 
filament ;  basal  cell  elongate  ;  terminal  cell,  which  is  some- 
times an  oogonium,  short  acute  or  acuminate ;  dwarf  males  on 
suffultory  cell,  stipe  slightly  curved  ;  antheridium  exterior,  1-3- 
celled. 

veg.  cell,  21-30  fj.  diam.,  3-8    diam.  long. 

suf.  cell,  45-56  M     "  1^-2        " 

oog.,  58-68  fj.     "  69-89  M  long. 

oos.,  56-66  M     "  65-83/11     " 

andr.  cell,  21-30/1*     "  18-25/11     " 

nan.  stipe,  15-24  /"•    "  54-6o  /*     " 

anth.  cell,  9-14  /u     "  7-11  M     " 

Greenland,  Mass.,  Conn.,  N.  J.,  Pa.,  Minn.,  Fla. 

Europe,  Asia,  So.  America. 

A  cosmopolitan  species,  and  generally  quite  uniform  in  its 
characters  ;  it  is  distinguished  from  Oe.  Botisianum  and  Oe.  con- 
catenatum  by  the  lines  on  the  oogonium  and  the  oospore,  the 
two  fitting  closely,  the  elevations  on  one  into  the  furrows  in 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  257 

the  other ;  Oc.  Borisianum  has  smooth  spores  ;  Oc.  concatcnatum 
has  dotted  lines  on  the  median  membrane  of  the  oospore,  but 
the  outer  membrane  and  the  oogonium  are  smooth.  One  form 
and  one  variety  are  to  be  noticed. 

Forma  INSIGNE  (Nordstedt)  Hirn,  1900,  p.  222,  PI.  XXXVII, 
fig.  227.  Stouter,  lines  on  the  oospore  and  oogonium  35-40, 
oogonia  i-io,  androsporangia  to  lo-celled,  antheridia  i-4-celled. 
The  dimensions  are  one-fourth  or  one-fifth  larger  in  all  parts 
than  in  the  typical  form.  N.  J.  Sweden. 

Var.  CONCINNUM  Hirn,  1900,  p.  222,  PI.  XXXVII,  fig.  228. 
Smaller ;  oospore  not  quite  filling  the  oogonium  ;  lines  on  the 
membrane  of  the  oospore  finely  crenulate.  The  dimensions  are 
about  one-tenth  smaller  than  in  the  type. 

Minn. 

58.  OE.    CONCATENATUM  (Hass.)  Wittrock,    1874,    p.   25; 
Wolle,  1887,  p.  81,   PI.  L,XXIX,   figs.    1-3,   and  var.  sctigeruni 
Wolle,  1887,  p.  82,  PI.  LXXIX  ,  figs.  4  and  5  ;   Hirn,  1900,  p. 
223,  PI.  XXXVIII,  fig.  230.     Dioecious,  nannandrous,  gynan- 
drosporous  ;  oogonia  single  or  2-6,  suboviform  or  quadrangular- 
ellipsoid,  pore  superior ;  oospore  same  form   as  the  oogonium, 
nearly  filling  it,  membrane  apparently  triple  ;  outer  membrane 
smooth,  median  membrane  with  pits,  more  or  less  distinctly  ar- 
ranged in  30-35  longitudinal  series,  inner  membrane  smooth  ; 
suffultory  cell  swollen;    androsporangia   i-4-celled;  basal   cell 
elongate,  terminal  cell  obtuse  ;  dwarf  males  curved,  on  sufful- 
tory cell ;  anthericlium  exterior,  i-4-celled. 

veg.  cell,  25-40  Mdiam.,  3-10    diatn.  long, 

suf.  cell,  50-62  fj.      "  1%-2'A      "        " 

oog.,  63-83^      "  76-105  ^  long, 

oos.,  .        60-76  p.      "  67-95    M 

andr.  cell,  25-28  /j.      :t  15-36    M     " 

nan.  stipe,  17-25  M      "  50-75    M 

anth.  cell,  13-15  M      "  12-25    M     " 

Mass.,  N.  J.,  Pa.,  Alaska.  Europe. 

Various  forms  of  this  species  are  found   in  Europe,  but  only 

the  type  has  been  recorded  in  this  country.     The  distinctions 

between  this  species  and  the  three  preceding  have  been  already 

indicated. 

59.  OE.  MULTISPORUM  Wood,  1869,  p.  141  ;  Wolle,  1887,  p. 
78,  PI.  LXXX,  figs.  6  and  7  ;  Hirn,  1900,  p.  232,  PI.  XXXIX, 
fig.  239.     Dioecious,  nannandrous  ;  oogonia  single  or  2-3,  sub- 
oviform  or  subglobose  (pore  superior  ?)  ;  oospore  globose,  nearly 


258  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

filling  the  oogonium  (membrane  smooth  ?)  ;  (suffultory  cell  of 
same  form  as  the  other  vegetative  cells  ?)  ;  dwarf  males  slightly 
curved,  near  the  oogonium  ;  antheridium  exterior,  i-  (or  more-?) 
celled. 

veg.  cell,  12-14  M  diaru.,         i%-i%  diam.  long. 

oog.,  31-35  M      "  28-33    M  long- 

COS.,  27-29  fJ.        "  25-29     fJ.      " 

nan.  stipe,  n  /»     "  26    n     " 

anth.  cell,  7-9    M    -  "  9    M     " 

Pa. 

The  description  is  incomplete,  but  is  all  that  can  be  obtained 
from  Wood's  figures  and  text ;  no  original  specimens  are 
known. 

60.  OE.  MACRANDRIUM  Wittrock,   1870,  p.    130,   PL  I,  figs. 
3-5  ;   Wolle,  1887,  p.  80,   PI.  LXXXII,  figs.    1-3  ;   Him,    1900, 
p.  233,  PL  XXXIX,   fig.    240;  Wittr.  and  Nordst.,  Alg.  Ex- 
sicc.,  Nos.    108,   505,    1217.     Dioecious,  nannandrous ;  oogonia 
single  or  2-3,   rarely  4  ;   globose-oboviform,  operculate,  division 
superior  ;  oospore  globose,  more  rarely  obovi form- globose,  not 
fully  filling  the  oogonium,  membrane  smooth  ;  suffultory  cell  of 
same  form  as  the  other  vegetative  cells  ;  terminal  cell  obtuse  or 
very  shortly  apiculate  ;  dwarf  males  on  or  near  the  oogonium, 
stipe  much  curved,  sometimes  2-3-celled  ;  antheridia  i-7-celled. 

veg.  cell,  15-20  p.  diam.,  3-5    diam.  long, 

oog.,  36-42  /*      "  43-54  /j.  long, 

oos.,  31-37  M      "  33-39  M     " 

nan.  stipe,  12-13  M      "  24-33^1     " 
anth.  cell,                     9-10  M      "  7-10  M     " 

Mass.,  Pa.  Europe, 

Var.  AEMULANS  Him,  1900,  p.  235,  PL  XXXIX,  fig.  242; 
Oe.  Lundense  Wolle,  1887,  p.  79,  PL  LXXVII,  figs.  9  and  10  ; 
Wittr.,  Nordst.  and  Lagerh.,  Alg.  Exsicc.,  No.  1402.  Some- 
what smaller  in  all  dimensions,  as  well  as  more  variable  ; 
oogonia  2-6. 

Pa.,  Cal.  So.  America. 

From  similar  American  species  this  is  distinguished  by  the 

manner  in  which  the  operculum  separates  from  the  lower  part 

of  the  oogonium  ;    the  parts   are  not  parallel,  but  more  as   if 

hinged  at  one  side  and  open  at  the  other. 

61.  OE.  LONGATUM  Kiitzing,  1853,  p.  n,  PL  XXXIII,  fig. 
6;  Wolle,  1887,  p.  95,  PL  LXXV,  fig.  3;  Him,  1900,  p.  239, 
PL  XL,,  fig.  248;  P.  B.-A.,  No.  812.    Dioecious,  nannandrous; 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  259 

oogonia  single  or  2,  more  rarely  3,  oviform  or  ellipsoid,  oper- 
culate,  division  superior ;  oospore  ellipsoid,  about  filling  the 
oogonium,  membrane  sometimes  very  finely  crenulate  ;  sufful- 
tory  cell  similar  to  other  vegetative  cells ;  basal  cell  elongate, 
terminal  cell  obtuse  ;  dwarf  males  on  the  oogonium  ;  anther- 
idium  exterior,  i-  (or  more-)  celled,  curved. 

veg.  cell,  4-7    fj.  diam.,  2-5    diam.  long, 

oog.,  16-18^      "  21-25  M  long, 

oos.,  15-17  M      "  17-19  /j.     " 

nan.  stipe,  5-6    M      "  10-15  /*     " 

anth.  cell,  4-5    M      "  5-6    M     " 

Mass.,  Pa.  Europe. 

A  very  slender  species,  usually  found  as  scattered  filaments 
among  other  species  of  Oedogonium.  The  curved  antheridia 
seem  peculiar  among  the  American  species. 

62.  OE.  ACROSPORUM  De  Bary,  1854,  pp.  47,  60,  94,  PI.  Ill, 
figs.  1-12;  Hirn,  1900,  p.  244,  PI.  XLI,  fig.  254;  Oc.  acro- 
spontm  var.  connectcns  P.  B.-A.,  No.  409.  Dioecious,  nannan- 
drous,  gynandrosporous  (or  idioandrosporous)  ;  oogonia  single, 
terminal,  ellipsoid,  operculate,  division  near  summit,  operculum 
minute,  deciduous;  membrane  of  oogonium  with  longitudinal, 
sometimes  anastomosing  ridges  on  the  inner  surface  ;  oospore 
quite  filling  the  oogonium,  the  outer  membrane  with  23-30 
longitudinal,  very  finely  crenulate  ridges,  closely  fitting  between 
the  ridges  of  the  oogonium,  and  connected  by  delicate  trans- 
verse striae  ;  inner  membrane  smooth  ;  suffultory  cell  somewhat 
swollen  ;  basal  cell  elongate,  terminal  cell  obtuse ;  androspor- 
angia  i-2-celled,  hypogynous ;  dwarf  males  curved,  on  the  suf- 
fultory cell,  stipe  sometimes  2-3-celled,  upper  cells  long, 
antheridium  exterior,  i-2-celled. 

veg.  cell,  13-21  fj.  diam.,  3-6    diam.  long, 

suf.  cell,  17-25  ft      "  il/2-T,        "         " 

oog.,  38-48  M      "  50-63  M  long, 

andr.  cell,  16-21  M      "  12-15  ^     " 

lower  cell,  nan.  stipe,  9-12  ^     "  30-38  M     ' 

upper  cell,  nan.  stipe,          6-8    /x      "  55-?i  M 

anth.  cell,  6-8    M      "  9-15  ^     " 

Mass.  Europe,  Asia,  So.  America. 

Our  only  species  of  Oedogonium  in  which  each  fertile  filament 
bears  one  terminal  oogonium,  and  none  elsewhere. 

Forma  BOREALE  (Wolle)  Hirn,  1900,  p.  245,  PI.  XLI,  fig. 
256  ;  Oe.  acrosporum  var.  boreale  Wolle,  1887,  p.  84,  PI.  LXXIX, 


260  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

figs.  10  and  n.  Filaments  of  few  cells,  vegetative  cells  shorter 
than  in  the  type,  14-16  /x  diam.,  3-5  diam.  long. 

N.  J.,  Pa. 

Probably  a  local  form. 

Var.  FLORIDENSE  Wolle,  1887,  p.  83,  PI.  LXXXV,  figs,  i 
and  2  ;  Hirn,  1900,  p.  246,  PI.  XLJ,  fig.  258.  A  slender  form, 
with  long  vegetative  cells,  suffultory  cells  more  swollen  than  in 
the  type  ;  dwarf  males  very  long,  stipe  2-3-celled. 

veg.  cell,  7-8    fj.  cliam.,  5-11  diaiu.  long. 

oog.,  33-35  M      "  45-50 /x  diam. 

Florida. 

Var.  BATHMIDOSPORUM  (Nordst.)  Hirn,  1900,  p.  246,  PI. 
XLJI,  fig.  259;  Oe.  acrosporum,  P.  B.-A.,  No.  163.  Smaller, 
with  fewer  ridges  on  oogonium  and  oospore,  about  11-17,  dis- 
tinctly crenate,  with  distinct  striae  between ;  stipe  of  dwarf 
male  unicellular. 

veg.  cell,  12-17  M  diam.,  3-8    diam.  long, 

suf.  cell,  15-22  fj.      "  2^2-5        "         " 

oog.,  30-40 /u      "  40-54  M  long, 

nan.  stipe,  9-11  p.      "  9-12  /u     " 

ANTHERIDIUM  INTERIUS,  PORIFERA,  ELLIPSOSPORA. 

63.  OE.  CYATHIGERUM  Wittrock,  1870,  p.  131,  PI.  I,  figs.  6 
and  7  ;  Hirn,  1900,  p.  252,  PL  XIJII,  fig.  265.  Dioecious, 
nannandrous,  idioandrosporous ;  oogonia  single  or  2-3,  subovi- 
form  or  quadrangular-ellipsoid,  pore  superior ;  oospore  same 
form  as  the  oogonium,  filling  it,  membrane  triple ;  outer  mem- 
brane smooth,  median  membrane  with  16-25  longitudinal, 
continuous,  rarely  anastomosing,  often  curved,  ridges,  inner 
membrane  smooth ;  basal  cell  elongate,  terminal  cell,  which 
sometimes  is  an  oogonium,  obtuse  ;  dwarf  males  goblet-shaped, 
curved,  on  the  suffultory  cell,  rarely  on  the  oogonium  ;  anther- 
idium  interior. 

veg.  cell, 
suf.  cell, 
oog., 
oos., 

anth.  cell, 
nan.  cell, 

The  type  is  European,  and  has  not  yet  been  found  in  this 
country.  We  have 

Forma  ORNATUM  (Wittrock)  Hirn,  1900,  p.  254,  PI.  XLJII, 


21-30  /u  diam., 

2-10    diam.  long. 

42-48  M       " 

1^-2'^      "         " 

57-66  /*      " 

70-100  M  long. 

51-62  /ix       " 

60-75     /u     " 

23-30  M       " 

12-30    fj.    " 

12-15  M       " 

50-58    /a     " 

THE  GRKEN  ALGAE  OF  NORTH  AMERICA  261 

fig.  267  ;  with  longer  dwarf  males,  60-75  /x,  and  slightly  longer 
oospores  ;  otherwise  like  the  type. 
Mexico. 

Forma  AMKRICANUM  Wolle,  1887,  p.  77,  PI.  LXXXI,  figs. 
20-22  ;  Him,  1900,  p.  256.  More  slender  than  the  type,  with 
shorter  vegetative  cells,  and  dwarf  males  on  the  oogonitim,  not 
on  the  suffultory  cell. 

veg.  cell,  17-21  M  diam.,  i  ',  ;,    diam.  long. 

oog.,  45-50  fj.      "  55-63  M  long. 

oos.,  39-40  n      "  44-46  fj.     " 

nan.  cell,  12-15  M      "  5°-54  /"•     " 

Pa. 

The  long,  goblet-  like  dwarf  males  are  characteristic  of  this 
species,  and  have  given  it  its  specific  name.  The  interior 
antheridium  is  often  hard  to  distinguish,  and  the  species  was  at 
first  described  as  having  unicellular  antheridia.  The  dwarf 
males,  with  the  much  swollen  suffultory  cells,  and  the  irregular 
lines  on  the  oospore,  make  a  combination  of  characters  that 
clearly  distinguishes  the  species,  and  this  combination  is  found 
in  all  the  forms  and  varieties. 


ANTHERIDIUM  INTERIUS,  ' 
64.  OR.  UNDUI.ATUM  (Breb.)  A.  Braun  in  De  Bary,  1854,  p. 
94;  Wolle,  1887,  p.  76,  PI.  LXXVII,  fig.  8;  Him,  1900, 
p.  257,  PI.  XL,V,  fig.  273;  Wittr.  and  Nordst.,  Alg.  Exsicc., 
No.  702,  in  part.  Dioecious,  nannandrous,  gynandrosporous  or 
idioandrosporous  ;  oogonia  single  or  2,  subglobose  or  ellipsoid- 
globose,  operculate,  division  inferior,  oospore  globose  or  sub- 
globose,  almost  filling  the  oogonium,  metnbrane  smooth,  gener- 
ally thick  ;  suffultory  cell  not  or  only  slightly  swollen  ;  andro- 
sporangia  to  7-celled  ;  vegetative  cells  four  times  undulate- 
constricted  ;  basal  cell  elongate,  not  undulate  ;  terminal  cell, 
which  sometimes  is  an  oogonium,  obtuse  ;  dwarf  males  elongate- 
obconic,  generally  on  the  suffultory  cell,  more  rarely  on  other 
vegetative  cells  near'  the  oogonium  ;  antheridium  interior. 

veg.  cell,  12-22  M  diam.,  3-5    diarn.  long. 

oog.,  48-56  M      "  50-75  M  long. 

oos.,  42-50  /u.      "  42-52  n     " 

andr.  cell,  15-21  fj.      "  7-14  M     " 

nan.  cell,  8-10  M      "  48-65  M    " 

Europe,  Australia,  So.  America. 

Reported  by  Wolle,  but  the  only  definite  American  locality 
recorded  is  Martha's  Vineyard,  Mass.,  and  the  plant  there   is 


262          TUFT'S  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Forma  SENEGALENSE  (Nordst.)  Hirn,  igoo,  p.  261,  PI.  XLV, 
fig-  277!  P-  B.-A.,  No.  73.  Oogonia  and  oospores  somewhat 
smaller  than  in  the  type,  dwarf  males  shorter ;  oogonia  to  5- 
seriate  ;  vegetative  cells  with  the  three  median  swellings  repand, 
the  terminal  swellings  entire. 

veg.  cell,  15-22  /u  diani.,  3-5    diam.  long. 

oog.,  42-52  V-      "  44-63  M  long.' 

oos.,  37-44  fJ-      "  36-44 /"•     " 

andr.  cell,  15-19  M      "  9-18  M     " 

nan.  cell,  6-8    n      "  37'44  /"     " 

Mass.  Africa. 

The  description  and  the  measurements  just  given  are  founded 
on  the  specimens  distributed  in  P.  B.-A.,  No.  73;  the  original 
forma  scnegalcnse  from  Africa,  has  oogonia  not  over  3-seriate,  and 
swellings  of  the  vegetative  cells  entire.  As  with  Oe.  cyathi- 
gcrnm,  so  in  this  species  the  antheridia  appear  to  be  unicellular 
unless  good  material  is  carefully  examined.  The  peculiar  form 
of  the  vegetative  cells  easily  distinguishes  it  from  all  our  other 
species,  Oe.  nodidosum  being  the  only  other  with  similar  con- 
strictions, but  there  is  no  danger  of  confounding  the  two,  if  the 
constrictions  are  counted  ;  these  two  are  our  only  species  which 
are  recognizable  even  when  sterile. 

NANNANDRES  UNICELLULARES  ;    OPERCULATA,  GLOBOSPORA. 

65.  OE.  ROTHII  (L,eCl.)  Pringsheim,  1858,  p.  69,  PI.  V,  fig. 
4;  Hirn,  1900,  p.  265,   PL  XLV,  fig.  282;  P.  B.-A.,  No.  520. 
Dioecious,   nannandrous,   gynandrosporous ;  oogonia   single  or 
2-3-seriate,  subdepressed- globose,  operculate,  division  median, 
narrow  ;  oospore  depressed-globose,  almost  filling  the  oogonium, 
membrane  smooth  ;  suffultory  cell  not  swollen  ;  androsporangia 
i-4-celled,  subhypogynous,  hypogynous,  subepigynous  or  scat- 
tered ;  dwarf  males  oboviform,  unicellular,  on  the  oogonium. 

veg.  cell,  6-iOMdiam.,  3-8    diam.  long, 

oog.,  20-27  M      "  16-27  M  long, 

oos.,  17-25  /J-      "  14-20 /u     " 

andr.  cell,  6-8    M      "  5-10  /u     " 

nan.  cell,  4  M      "  11-12  /u     " 

Mass.  Europe. 

66.  OE.    DECIPIENS  Wittrock,    1874,  p.  18;  Wolle,  1887,  p. 
75,  PI.  LXXVII,  figs.  5  and  6;   Hirn,  1900,  p,  266,  PL  XLVI, 
fig.  283;  Wittr.  and  Nordst.,  Alg.  Exsicc.,    No.  602,  in  part. 
Dioecious,   nannandrous,  gynandrosporous  ;  oogonia  single,  or 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  263 

2-3,  subdepressed-globose,  operculate,  division  median,  rather 
narrow  ;  oospore  subdepressed  or  depressed-globose,  almost  fill- 
ing the  oogonium,  membrane  smooth ;  suffultory  cell  not 
swollen ;  androsporangia  to  6-celled,  subepigynous,  hypogy- 
nous  or  scattered ;  dwarf  males  obovifortn,  unicellular,  on 
the  oogonium. 

veg.  cell,  9-12  fj.  diam.,  3-5    diam.  long, 

oog.,  30-38/1*      "  27-40  /j.  long, 

oos.,  25-34  /j.      "  23-28  n     " 
andr.  cell,                       9-10 /u      "  8-15  /u     " 

nan.  cell,  6-7    /j.      "  13-15  M     " 

N.  J.,  Iowa.  Europe. 

Somewhat  resembling  Oe.  Rothii,  but  a  larger  plant. 

67.  OE.  ARESCHOUOII  Wittrock,  1870,  p.  122,  PI.  I,  figs,  i 
and  2  ;  Wolle,  1887,  p.  76,  PI.  LXXVII,  fig.  7  ;  Him,  1900,  p. 
270,  PI.  XI/VI,  fig.  289.  Dioecious,  nannaudrous,  gynaudro- 
sporous ;  oogonia  2-6  or  single,  subdepressed-  or  depressed- 
pyriform-globose,  operculate,  division  median,  broad  ;  oospore 
globose,  rarely  subdepressed-globose,  not  nearly  filling  the 
oogonium,  membrane  smooth  ;  suffultory  cell  of  the  same  form 
as  the  other  vegetative  cells;  androsporangia  i -6-celled,  sub- 
epigynous or  hypogynous,  or  more  rarely  scattered  ;  vegetative 
cells  capitellate  ;  basal  cell  elongate,  terminal  cell,  which  some- 
times is  an  oogonium,  obtuse ;  dwarf  males  oboviform,  unicel- 
lular, on  the  oogonium. 

veg.  cell,  8-13  M  diam.,  4-6    diam.  long, 

oog.,  34-39  M      c<  36-40  M  long, 

oos.,  22-26  M      "  22-25 /j.    " 

andr.  cell,  9-11  n      "  10-12 /a    " 

nan.  cell,  .      6-7    M      "  13-15  M     " 

Greenland,  N.  J.  Europe,  So.  America. 

Forma  ROBUSTUM  Him,  1900,  p.  271,  PI.  XL,VI,  fig.  290. 
Idioandrosporous ;  larger  in  all  parts  than  the  type,  especially 
as  to  the  vegetative  cells  ;  oogonia  to  8-seriate. 

veg.  cell",  12-17  M  diam.,  3-6    diatn.  long, 

oog.,  36-40  M      "  36-53  M  long, 

oos.,  30-32  n      "  27-31  M     " 

andr.  cell,  9-12  M      "  10-13  M     " 

nan.  cell,  6-8    M      "  14-15  /a     " 

England. 

Him  includes  provisionally  under  this  form  the  plant  from 
Minnesota,  distributed  in  Tilden,  American  Algae,  No.  3,  as 


264          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Oe.  obtruncatum  var.  oblatum  Tilden,  though    the    dimensions 
vary  somewhat,  being 

veg.  cell,  15-20  /j.  diam.,         1/4-2%  diam.  long. 

oog.,  37-42  M      "  35-38    /ilong. 

68.  OE.  PLATYGYNUM  Wittrock,  i872a,  p.  i  ;  Wolle,  1887,  p. 
75,  PI.  LXXVII,  figs.  1-4;  Him,  1900,  p.  276,  PI.  XLVII,  fig. 
301  ;    Wittr.,  Nordst.  and  L,agerh.,   Alg.   Exsicc.,    No.    1218. 
Dioecious,   nannandrous,  gynandrosporous   and   idioandrospor- 
ous  ;  oogonia  single  or  very  rarely  2,  depressed-oboviform,  with 
7-12  rounded  prominences  arranged  in  a  whorl  around  the  middle, 
operculate,    division    inferior ;    oospore    depressed-    or   subde- 
pressed-globose,    not    quite    filling    the   oogonium,    membrane 
smooth  ;  suffultory  cell  not  or  slightly  swollen  ;  androsporangia 
i -3  celled;    vegetative    cells   slightly  capitellate,   terminal   cell 
obtuse  ;   dwarf  males  unicellular,  oboviform,  ve^  small,  on  the 
oogonium. 

veg.  cell, 
oog., 
oos., 

andr.  cell, 
nan.  cell, 

N.  J.,  Pa.,  Fla.,  Minn.  Europe,  So.  America. 

The  peculiar  form  of  the  oogonium,  with  the  whorl  of  projec- 
tions, is  not  found  in  any  other  American  species. 

69.  OE.   PLUVIALE  Nordstedt  in   Rabenhorst,   Algen.,   No. 
2257;  Him,  1900,  p.  280,  PI.  XLVIII,  fig.  311  ;   P.  B.-A.,  No. 
1190.     Oe.  fonticola  Wolle,    1887,    p.   93,   PL  L,XXV,  figs.  4-6. 
Dioecious,  nannandrous,  idioandrosporous  ;  oogonia  single,  very 
rarely  2-3,   oboviform-globose  or  subglobose,  operculate,    divi- 
sion   superior ;     oospore    subglobose    or    subellipsoid-globose, 
almost   filling   the   oogonium,    membrane    smooth ;    suffultory 
cell  not  swollen  ;  vegetative  cells  varying  much  in  diameter  in 
the  same  individual ;  basal  cell  elongate,  terminal  cell  obtuse  ; 
androsporangial  plants  often  somewhat  more  slender  than  the 
female ;    androsporangia    to    lo-celled ;    dwarf    males    broadly 
oboviform,  unicellular,  on  the  oogonium. 

veg.  cell,  female,  22-29  v-  diam.,  ^-2    diam.  long, 

veg.  cell,  male,  18-27  f-      "  1-2        "         " 

oog.,  34-45  M      "  34-50  /*  long, 

oos.,  32-40  n      "  31-43  p     « 

andr.  cell,  17-25  M      "  6-13  n     " 

nan.  cell,  10 /x      "  14- ISM     " 

Cal.  Europe. 


6-io  /u,  diam., 

2-5     diam.  long. 

21-30  /x 

it 

16-24   / 

x  long. 

17-24  /* 

x 

15-20 

v-     " 

6-8    M 

" 

7-8 

f.    '•' 

4-5-5    M 

n 

8.5-9-5 

/x     " 

THE  GREEN  ALGAE  OF  NORTH  AMERICA  265 

Wolle  says  frequent,  but  gives  no  definite  locality.  The  con- 
siderable variation  both  in  length  and  diameter  of  cells  in  the 
same  plant,  is  quite  noticeable. 


SPKCIES  OF  WHICH  THK  ORGANS  OF  FRUCTIFICATION  ARE 
PARTLY  KNOWN. 

70.  OB.  GIGANTEUM  Kiitzillg,    1845,  p.  2OO  ;    Wolle,    1887,  p. 

94,  PI.  LXXVI,  figs.  1-6  ;  Him,   1900,  p.  295,  PI.  XXIII,  fig.  , 
115;   Phyk.  Univ.,  No.  177.     Oogonia  single,  slightly  swollen, 
cylindric-oboviform,   pore  superior;   oospore  cylindric-ellipsoid 
or  subellipsoid,  nearly  filling  the  oogonium,  membrane  appar- 
ently triple;  outer  membrane  smooth,  median  with  25-30  longi- 
tudinal series  of  pits  ;  inner  membrane  smooth  ;  suffultory  cell 
often  larger  than  the  other  vegetative  cells,  but  not  swollen. 

veg.  cell,  30-50  fj.  diam.,  2-4/4  diam.  long. 

suf.  cell,  40-60  M      "  i)4-3/4      "        " 

oog.,  53-69  M      "  67-106  n  long. 

oos.,  51-65  M      "  65-103/4     " 

Mentioned  by  Wolle,  but  without  exact  locality  ;  we  have  no 
other  species  with  similar  markings  to  the  spore. 

71.  OE.  PYRIFORME  Wittrock,  1874,  p.  39;  Wolle,  1887,  p. 

95,  PI.  LXXVII,  figs.  11-13;  Him,    1900,   p.  303,    PL  XXV, 
fig.  137.     Oogonia  single,  pyrifonn,  operculate  ;  antheridia  2-3- 
celled,  subepigynous,  hypogynous  or  scattered. 

veg.  cell,  13-16  /u  diani.,          3/^-6    diam.  long. 

oog.,  40-45  M      "  54-6o  n  long. 

Panth.  cell,  10-12  M      "  9-12/1     " 

N.  J.  Australia. 

A  very  imperfectly  known  species  ;  but  the  form  of  the 
oogonium  is  peculiar;  pyriform,  or  perhaps  better,  "top- 
shaped." 

72.  OE.  SANCTI  THOMAE  Wittrock  and  Cleve  in  Wittrock, 
1874,  p.  40  ;   Him,  1900,  p.  304,  PI.  XXIX,  fig.  173.     Oogonia 
single  or  2-3,  pyriform,  operculate,  division  superior;  oospore 
pyriform-oboviform,  not  quite  filling  the  oogonium,  membrane 
smooth  ;    basal  cell  subhemispherical,  not  elongate  ;    terminal 
cell  very  slender,  subhyaline. 

veg.  cell,  7-15  M  diam.,  2-6    diam.  long. 

term,  cell,  2-4    M      "  5-7 

oog.,  28-33  /J.      "  36-50  /t 

oos.,  25-30  M      "  28-35  M 

basal  cell,  14-23  M      "  8-12  M 
St.  Thomas,  W.  I. 


266          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Somewhat  resembling  Oe.  pyriformc,  but  a  smaller  plant,  and 
with  peculiar  basal  and  terminal  cells. 

73.  OE.   CATARACTUM  Wolle,   1887,   p.   77,   PL    LXXXV, 
figs.  10-12  ;  Him,  1900,  p.  308,  PI.  XL,II,  fig.  264.     Dioecious, 
nannandrous,  idioandrosporous ;  oogonia  single  or  2,  often  ter- 
minal,  oboviform-globose,   subglobose    or    broadly   ovate,   pore 
superior ;  oospore  globose  or  oboviform-globose,   almost  filling 
the  oogonium ;  androsporangia  2-6-celled,   dwarf   males   much 
curved,  on  suffultory  cell  or  sometimes  on  the  cell  below  this; 
antheridium  interior  ? 

veg.  cell,  28-38 /u  diam.,          J>£-3    diain.  long, 

oog.,  55-60  M     "  60-75  M  long. 

COS.,  50-55  M      "  50-60  M      " 

andr.  cell,  26-30  /x     "  jo-15  M     " 

nan.  cell,  10  M     "  65  M     " 

Pa. 

Although  this  description  appears  to  be  fairly  complete,  the 
species  is  placed  by  Hirn  among  those  insufficiently  known,  as 
Wolle's  statements  in  regard  to  the  male  plant  are  contradictory  ; 
this  being  given  as  unicellular  and  also  as  having  internal  an- 
theridia.  Hirn  suggests  that  it  may  be  a  form  of  Oe.  crassius- 
culmn . 

74.  OE.  LONDINENSE  Wittrock,    1874,  p.  39;   Wolle,  1887, 
p.  94,  PI.  IvXXV,  figs.  7  and  8  ;   Hirn,  1900,  p.  317.     Oogonia 
2  or  i,  globose,  division  median,  oospore  globose,  almost  filling 
the  oogonium ;  antheridia  (or  androsporangia?)   i-2-celled,  hy- 
pogynous. 

veg.  cell,  10-15 /x  diani.,         I/^-5    diam.  long, 

oog.,  33-35  M      "  33-43  M  long. 

OOS.,  27-32  ft        "  27-32  M      " 

anth.  cell?  12  A1      "  10-11  M     " 

N.  J.,  according  to  Wolle.  A  very  imperfectly  known  species, 
and  American  only  with  some  doubt,  there  being  no  other  record 
than  Wolle's. 

2.  BULBOCHAETE  Agardh,  1817,  p.  XXIX. 
Filaments  branching ;  vegetative  cells  increasing  in  size  to 
upper  end  ;  basal  cell  often  lobed,  attached  to  substratum  ;  ter- 
minal cell  of  each  filament  and  branch  produced  into  a  long, 
hyaline  seta  with  a  bulbous  base ;  plant  increasing  mostly  by 
division  of  the  basal  cell  of  the  principal  filament  or  of  a  branch  ; 
oogonia  arising  by  a  double  division  of  a  vegetative  cell. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  267 

There  is  no  danger  of  mistaking  a  Bulbochacte,  even  in  the 
sterile  condition,  for  any  other  alga  ;  the  erect,  branching  frond, 
with  cells  larger  at  their  top  than  at  their  bottom,  and  every 
branch  ending  in  a  long  seta  with  a  bulbous  base,  are  unmis- 
takable characters.  In  the  determination  of  species  much  the. 
same  distinctions  are  used  as  in  Oedogonium^  and  also  charac- 
ters drawn  from  the  formation  of  the  oogonium  ;  as  this  arises 
by  a  double  division  of  the  vegetative  cell,  the  suffultory  cells 
are  two,  and  according  as  the  upper  of  the  two  is  longer  or 
shorter  than  the  lower,  or  of  the  same  length,  we  have  the  char- 
acters, dissepiment  inferior,  superior  or  median.  If  the  two 
partition  walls  have  formed  directly  across  the  axis  of  the  orig- 
inal cell,  we  have  oogonium  erect ;  if  one  of  them  is  oblique, 
giving  one  of  the  cells  a  five-angled  appearance  in  section,  we 
have  oogonium  patent. 

The  species  of  Bulbochaetc  are  found  in  the  same  stations  as 
Ocdogonium,  and  though  not  so  common  as  species  of  the  latter, 
they  are  by  no  means  infrequent,  and  are  distributed  all  over 
the  world. 

KEY  TO  THE  SPECIES  OF  BULBOCHAETE. 

i.     Spores  globose.  2. 

I.     Spores  ellipsoid.  10. 

2.     Oogonia  erect.  i.     B.  Brebissonii. 

2.     Oogonia  patent.  3- 

3.     Oogonia  60  /j.  diam.  or  more.  4- 

3.     Oogonia  not  over  56  /n  diam.  5- 

4.     Gynandrosporous.  8.    B.  setigera. 

4.     Idioaudrosporous.  18. 
5.     Oogonium  biconic-  or  subquadrangular-globose.      7.     B.  augulosa. 

5.     Oogonium  depressed-  or  subdepressed-globose.  6. 

6.     Dissepiment  of  suffultory  cell  about  median.  7. 

6.     Dissepiment  of  suffultory  cell  superior. 

7.     Membrane  of  oospore  minutely  crenulate.  2.     B.  intermedia. 

7.     Membrane  of  oospore  strongly  creuulate.  3.     B.  crenulata. 

8.     Oogouia  44-56  A*  diam.  6.     B.dispar. 

8.     Oogonia  rarely  equalling  46  M-  9- 

9.     Gynandrosporous.  4-     B.  Nordstedtii. 

9.     Idioandrosporous.  5-     B.  polyandria. 

10.     Monoecious.  IT- 

10.     Dioecious.  T3- 


268          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

ii.     Vegetative  cells  about  as  loug  as  broad,  moniliform. 

ii. 
ii.     Vegetative  cells  longer  than  broad,  subcylindrical.  12. 

12.     Oogonium  20-25  M  diam.  12.     B.  nana. 

12.     Oogonium  26-35  M  diam.  13.     B.  mirabilis. 

13.     Suffultory  cell  without  dissepiment.  14.     B.pygmaea. 

13.     Suffultory  cell  with  dissepiment.  14- 

14.     Oogonium  about  i^  times  as  long  as  broad.  15. 

14.     Oogonium  about  1^4  times  as  long  as  broad  or  more. 

19.     B.  minor. 

15.     Oogonium  26-39  M  diam.  16. 

15.     Oogonium  44-60  /JL  diam.  18.     B.  insignis. 

16.     Vegetative  cells  repand.  17.     B.  rcpanda. 

16.     Vegetative  cells  cylindrical.  17- 

17.     Cells  rectangular  in  longitudinal  section.      16.     B.  redangularis. 
17.     Cells  oval  or  subtriangular  in  longitudinal  section. 

15.     B.  varians  f.  snbsiniple.r. 

18.     Dwarf  males  shorter  than  the  oogonium.       9.     B.  crassinscula. 

18.     Dwarf  males  longer  than  the  oogonium.  10.     B.  gi-gantea. 

GLOBOSPORAE. 

1.  B.  BREBISSONII  Kiitzing,  1855,  p.  19,   PL  LXXXVI.B  ; 
Him,   1900,  p.  323,  PI.  1,1,  fig.  330;  Rabenhorst,  Algen,  No. 
1055.       Dioecious,     nannandrous,     gynandrosporous  ;    oogoiiia 
depressed-subquadrangular-globose,  erect,  below  terminal  setae 
or  androsporangia  ;    dissepiment  of  suffultory  cell  very   low  ; 
epispore  of  oospore  scrobiculate  ;    androsporangia  scattered  or 
epigyuous,  i-3-celled  ;  dwarf  males  on  oogonia,  more  rarely  near 
them,  antheridium  interior,  stipe  slightly  curved,  shorter  than 
the  antheridium. 

veg.  cell,  17-20  /u.  diam.,  3-4/^  diam.  long. 

oog.,  42-50  fj.    "  37-45    Mlong. 

andr.  cell,  11-15  M     "  12-18    M     " 

nan.,  10-12  //.     "  28-33    ^     " 

Mass.,  Alaska.  Northern  Europe. 

The  only  species  with  interior  antheridium  and  erect  oogonia. 

2.  B.  INTERMEDIA  De  Bary,  1854,  p.  72,  PI.  IV,  figs.  1-7; 
Wolle,   1887,    p.    97,  PI.  LXXXVI,    figs.  1-3  ;    Him,  1900,  p. 
326,  PI.  1,11,  fig.  333;  P.  B.-A.,  No.  973.     Dioecious,  nannan- 
drous, gynandrosporous  ;    oogonia  sub-depressed-globose,  pat- 
ent, below  the  androsporangia  ;  dissepiment  of  suffultory  cells 
about  median  ;  epispore  of  oospore  pitted  or  more  rarely  smooth- 
ish ;  androsporangia  i-,  rarely  2-celled,  epigynous,  more  rarely 
scattered  ;    dwarf  males  on    oogonium  ;    antheridium  interior, 
stipe  slightly  curved,  shorter  than  the  antheridium.     Fig.  82. 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  269 

veg.  cell,  17-20 /u  diam.  2-3  '<  diain.  long. 

oog.,  40-48  M     "  31-40    M  long. 

andr.  cell,  11-13,1*     "  7-12    fj.     " 

nan.,  9-10  /u.     "  21-26    M     " 

Greenland,  Conn.,  Pa.,  Alaska.  l\uropt\  Australia. 

Forma  SUPRAMKDIANA  (Wittr.)  Hirn,  1900,  p.  328,  PI.  IJI, 
fitf-  335  I  Wittr.  and  Norclst.,  Alg.  Kxsicc.,  No.  509,  in  part. 
Oogonia  smaller,  usually  below  the  terminal  setae  ;  dissepiment 
of  suffultory  cells  somewhat  above  the  middle,  rarely  quite  near 
the  middle  ;  androsporangia  scattered. 

veg.  cell,  17-20  fj.  diam.,  2-3    diam.  long. 

oog.,  40-45  n      "  32-37  n  long. 

anth.  cell,  11-12  M      "  7-11  M     " 

nan.,  9-10  n      "  20-25/0.     " 

Pa. 

A  common  species  and  variable  ;  the  plants  distributed  as  P. 
B.-A.,  No.  973,  have  vegetative  cells  and  oogonia  somewhat 
more  slender  than  in  the  type. 

3.  B.  CRENUivATA  Pringsheim,  1858,   p.  72,  PI.  VI,  fig.  4; 
Wolle,  1887,  p.  97,  PI.   IvXXXVI,  fig.  4;   Hirn,  1900,  p.  331, 
PI.  LIU,  fig.  337.     Wittr.  and  Nordst.,  Alg.  Exsicc.,  No.  602, 
in  part.      Dioecious,  nannandrous,  gynandrosporous ;   oogonia 
subdepressed-globose,  patent,  below  the  terminal  setae  or  the 
androsporangia,  rarely  under  vegetative  cells  ;  dissepiment  of 
suffultory  cells  usually  median  or  slightly  lower ;    epispore  of 
oospore  distinctly  pitted  ;    androsporangia  epigynous  or  scat- 
tered, i-5-celled  ;  dwarf  males  on  oogonium  or  near  it,  antherid- 
ium  interior,  stipe  slightly  curved,  shorter  than  the  antheridium. 

veg.  cell,  16-20  fj.  diam.,  2-3^  diam.  long, 

oog.,  43-48  M      "  35-43    M  long, 

anth.  cell,  10-15  n      "  7-JO    M     " 

nan.,  9-10 /u      "  24-26    ,u     " 

Europe,  Australia. 

Quite  doubtfully  American,  there  being  no  authority  other 
than  Wolle's  description  and  figures. 

4.  B.  NORDSTEDTII  Wittrock,   1874,  p.  44;  Hirn,  1900,  p. 
332,  PI.  LIU,  fig.  340  ;  P.  B.-A.,  No.  717.     Dioecious,  nannan- 
drous, gynandrosporous  ;  oogonia  depressed  sub-quadrangular- 
globose  or  depressed-globose,  patent,  below  the  androsporangia, 
or  very  rarely  below  the  terminal  setae  ;  dissepiment  of  sufful- 
tory cells  superior,  rarely  sub-median  ;  epispore  of  oospore  finely 
pitted   or  nearly  smooth  ;    androsporangia  i -celled,  epigynous  ; 
dwarf  males  on  oogonium  ;  antheridium  interior,  stipe  slightly 
curved,  shorter  than  the  antheridium. 


270          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

veg.  cell,  14-17  M  diain.,  2-5    diarn.  long, 

oog.,  36-43  n      "  29-36/1  long, 

andr.  cell,  10-12  M      "  9-12  /u     " 

nan.,  9-10  /*      "  23-25  M     " 

Greenland,   Conn.,  Alaska.  Europe,  Australia. 

5.  B.  POLYANDRIA  Cleve  in  Wittrock,  1870,  p.  140  ;   Wolle, 
1887,  p.  98,   PI.   LXXXIX,  figs.  6-9;  Him,  1900,  p.  334,  PL 
LJV,    fig.    342.      Dioecious,    nannandrous,    idioandrosporous; 
oogonia  subdepressed-globose,  patent,  under  terminal  setae  or 
vegetative  cells  ;  dissepiment  of  suffultory  cells  superior,  more 
rarely  submedian  ;  epispore  of  oospore   finely  pitted  or  nearly 
smooth  ;  androsporangia  lo-celled  ;  dwarf  males  on  oogonium  ; 
antheridium   interior,   stipe   slightly    curved,   shorter   than   the 
antheridium. 

veg.  cell,  15-20  M  diam.,  3-5    diatn.  long, 

oog.,  39-46  n      "  32-42  p.  long, 

audr.  cell,  12-14  M      "  11-15  M     " 

nan.,  8-9    M      "  23-26  M    " 

Fla.  Europe,  So.  America, 

6.  B.  DISPAR  Wittrock  in  Wittr.  and  Nordst.,  Alg.  Exsicc., 
No.  401  ;  Him,   1900,   p.  335,  PI.  LJV,   fig.  334-     Dioecious, 
nannandrous,  gynandrosporous  or  idioandrosporous  ;  oogonium 
large,  subdepressed-globose,    patent,  under  terminal  setae,  or 
more  rarely  under  vegetative  cells  ;  •  dissepiment  of   suffultory 
cells  superior,    more  rarely  sub-median  ;  membrane  of  oospore 
thick,  epispore  manifestly  finely  pitted  ;    androsporangia  scat- 
tered, i-2-?-celled  ;  dwarf  males  on  oogonium  ;  antheridium  in- 
terior, stipe  slightly  curved,  shorter  than  the  antheridium. 

veg.  cell,  16-21  /j.  diam.,  2-4^  diam.  long, 

oog.,  44-56  /*      "  42-51    M  long, 

andr.  cell,  12-16  /u      "  10-12    /u     " 

nan.,  9-11  M      "  23-36    M     " 

Greenland.  Sweden. 

7.  B.  ANGULOSA  Wittrock  and   Lund  in  Wittrock,  1874,  p. 
45;   Hirn,    1900,   p.  336,    PL    LIV,   fig.   346;    B.  elachistandra 
Wolle,    1887,  p.   97,   PL    LXXXXVI,  fig.  5.     Dioecious,  nan- 
nandrous, gynandrosporous;  oogonia  patent,    biconic-   or  sub- 
quadrangular-globose,  with  truncate  apex,  sides  of  cone  some- 
what retuse,  below  terminal  setae,  or  more  rarely  below  andro- 
sporangia ;  dissepiment  of  suffultory  cells  a  little  above  median  ; 
membrane  of  oospore  smooth  ;  androsporangia  scattered  or  epi- 
gynous,    i-3-celled ;    dwarf    males   on   oogonium,    antheridium 
interior,  stipe  slightly  curved,  shorter  than  the  antheridium. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA          271 

veg.  cell,  13-18  /u  diam.,        i%-2%  diam.  long. 

°og.,  36-42  M      "  33-39    M  long, 

andr.  cell,  10-11  M      "  9-10    M     " 

nan.,  8-9    M      "  18-21    m     " 

Europe,  Africa. 
American  only  by  Wolle's  reference. 

8.  B.  SETIGERA  (Roth)  Agardh,   1817,  p.  71;  Wolle,   1887, 
p.  98,  PI.  LXXXVI,  fig.  i  ;  Wittr.  and  Nordst,  Alg.  Exsicc., 
No.  702  ;  Him,  1900,  p.  339,  PI.  L,V,  fig.  351.     Dioecious,  nan- 
nandrons,    gynandrosporous ;    oogonia    sub-depressed-    or   de- 
pressed-quadrangular-globose, patent,  generally  below  terminal 
setae,  more   rarely  below  androsporangia   or  vegetative  cells ; 
membrane  of  oospore  thickened  ;  dissepiment  of  suffultory  cells 
usually  slightly   above   median ;    epispore   of   oospore   pitted  ; 
androsporangia  scattered  or  more  rarely  epigynous,  i-3-celled  ; 
dwarf   males   on   oogonium   or  near  it  ;    antheridium   interior, 
stipe  slightly  curved,  shorter  than  the  antheridium. 

veg.  cell,  25-28  M  diam.,  2^-5    diam.  long, 

oog.,  70-80  M     "  56-65  n  long, 

andr.  cell,  16-20  /u      "  10-18  /u.     " 

nan.,  11-14  M      "  30-36  /u.     " 

Conn.,  N.  J.,  Fla.,  S.  C.  Europe,  So.  America. 

B.  Canbyi  Wood,  1872,  p.  202,  PI.  XVI,  fig.  6,  is  considered 
by  Hirn  to  be  included  in  this  species. 

9.  B.  CRASSIUSCULA  Nordstedt,  1877,  p.  30,  PI.  Ill,  figs.  14- 
15;   Hirn,  1900,  p.  341,   PI.  L,V,  fig.  352;   Wittr.  and  Nordst., 
Alg.  Exsicc.,   No.  703.      Dioecious,   nannandrous,    idioandro- 
sporous  ;     oogonia  depressed-subquadrangular-globose,  patent, 
below  terminal  setae  or  more  rarely  vegetative  cells ;   dissepi- 
ment  of   suffultory  cells   superior,   rarely  submedian  ;  epispore 
of  oospore  pitted;    androsporangia  i-4-celled;    dwarf  males  on 
oogonium  or  near  it ;  antheridium  interior,  stipe  slightly  curved, 
shorter  than  the  antheridium. 

veg.  cell,  22-27  M  diam.,        2^-5^  diam.  long, 

oog.,  60-78  fj.      "  50-62    M  long, 

anth.  cell,  16-19  M      "  *°-l3    f*    " 

nan.,  12-14  M      "  3°-34    M     " 

Greenland.  Europe,  Australia. 

10.  B.  GIGANTEA  Pringsheim,   1858,  p.  71,   PI.   VI,  fig.  i  ; 
Wolle,  1887,  p.  99,  PL  LXXXVII,  fig.  i  ;  Him,  1900,  p.  347,  PI. 
LVII,    fig.    359.     Dioecious,    nannandrous,    idioandrosporous ; 
oogonia  sub-depressed-globose  or  depressed-oboviform-globose, 
patent,  below  terminal  setae,  rarely  below  vegetative  cells;  dis- 


272  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

sepiment  of  suffultory  cells  submedian ;  epispore  of  oospore 
reticulately  pitted;  androsporangia  i-5-celled;  dwarf  males 
slightly  longer  than  the  oogonium,  on  the  same  ;  antheridium 
interior,  stipe  about  twice  as  long  as  the  antheridium,  bent. 

veg.  cell,  24-32  fj.  diam.,  2-3J4   diam.  long, 

oog.,  60-70  ,a      "  50-58    /a  loug. 

andr.  cell,  18-20  /u,      "  10-14    f-     " 

nan.  stipe,  10-13  M      "  28-45    M.    " 

anth.  cell,  13-14/1*      "  20-30    M     " 

Pa.  Europe,  Australia. 

KLLIPSOSPORAE. 

11.  B.  MONILE  Wittrock  and  Lund  in  Wittrock,  1874,  p.  50; 
Him,   1900,  p.  348,   PI.   LVII,  fig.  360;  P.  B.-A.,  No.  1432; 
B.  nana  Wolle,  1887,  p.    100,   PI.   LXXXVII,   fig.  6.     Monoe- 
cious, generally  few-celled,  vegetative  cells  short,  hardly  as  long 
as  broad,  sides  often  convex,  cells  then  submoniliform  or  sub- 
globose  ;  oogonia  ellipsoid,   patent  or  more  rarely  erect,  below 
terminal  setae  or  vegetative  cells ;   antheridia  i-2-?-celled,  erect 
or  patent,  subepigynous  or  scattered. 

veg.  cell,  11-16  /u.  diam.,  i    diam.  long, 

oog.,  22-25  n      "  30-37  n  loug. 

auth.  cell,                     8-10  M      "  6  8    /a     " 

Mass.,  N.  J.  Sweden. 

12.  B.  NANA  Wittrock,  i872a,  p.  7,  PI.  I,  fig.  9  ;   Hirn,  1900, 
p.    349,    PI.  LVII,    fig.  362.     Monoecious;    oogonia  ellipsoid, 
patent,  below  terminal  setae  or  vegetative  cells;  antheridia  1-2- 
celled,  erect,  more  rarely  patent,  subepigynous  or  scattered. 

veg.  cell,  10-15  M  diam.,  i-i>£  diam.  long, 

oog.,  20-25  M      "  33-4°    Mong. 

anth.  cell,  7-9    M      "  6-9      fj.     " 

Greenland,  Alaska.  Europe. 

13.  B.  MIRABILIS  Wittrock,    1870,   p.  137,    PI.  I,  figs.  8  and 
9;  Wolle,    1887,   p.   100,    PI.  LXXXVII,  figs.  2  and  3  ;  Him, 
1900,  p.  351,  PI.  I, VIII,  fig.  365;   P.  B.-A.,  No.  1431.     Monoe- 
cious ;    oogonia  ellipsoid  or  suboblong-ellipsoid,  patent,  or  more 
rarely  erect,  below  terminal  setae  or  vegetative  cells  ;  anther- 
idia i-4-celled,  erect  or  patent,  subepigynous  or  scattered. 

veg.  cell,  15-20  M  diam.,         i#-2    diam.  long, 

oog.,  26-33  n      "  46-58  M  long, 

anth.  cell,  9-12  n      "  6-9    n     " 

Greenland,  N.  J.,  Minn.  Europe,  Australia. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  273 

14.  B.  PVC.MAEA  Pringsheim,    1858,  p.   74,   PI.  VI,  fig.  10; 
Wolle,  1887,  p.  ioo,  PI.  LXXXVIL  figs.  4  and  5  ;  Wittr.  and 
Nordst.,  Alg.  Exsicc.,   Nos.  4,    1401  ;   Hirn,    1900,  p.   356,  PI. 
IvIX,    fig.    372.      Dioecious,  nannandrous,   gynandrosporous ; 
vegetative  cells  short,  not  longer  than  wide  ;  primary  filament 
of  the  plant  curved,  short ;  oogonia  ellipsoid,  patent,  below  ter- 
minal setae  or  vegetative  cells ;  suffultory  cell  without  dissepi- 
ment;    androsporangia  subepigynous  or  scattered,    i-?-celled  ; 
dwarf  males  near  oogonium,  antheridium  exterior,  i-3-celled. 

veg.  cell,  11-15  ft  diam.,  %-i    diam.  long, 

oog.,  22-25  M      "  32-40  M  ^long. 

andr.  cell,  7-10  ft      "  6-9    ft      " 

nan.  stipe,  11-12  M      "  15-19^       " 

anth.  cell,  7-8    /JL      "  7-8    ft      " 

Europe. 
Only  American  authority  Wolle's  reference. 

15.  B.  VARIANS  var.  SUBSIMPLEX  (Wittr.)   Him,    1900,   p. 
357,  Pis.  LJX,  LX,  fig.  374;  B.  subsimptexWotte,  1887,  p.  101, 
PI.  XC,   fig.   5.      Dioecious,   nannandrous,    gynandrosporous; 
oogonia  ellipsoid,  erect  or  more  rarely  patent,  below  terminal 
setae,  androsporangia  or  vegetative  cells  ;  androsporangia  scat- 
tered, epigynous  or  subepigynous,    i-2-?-celled  ;    dwarf  males 
near  or  on  oogonium  ;  antheridium  exterior,  i-3-celled. 

veg.  cell,  T3-i8Mdiam.,  i^-i^  diam.  long, 

oog.,  26-30  ft      "  39-46    ft  long, 

andr.  cell,  10-14  M      "•  7-16    ft    " 

nan.  stipe,  11-14  ft      "  15-24    ft    " 

anth.  cell,  7-8    M      "  5-7      M     " 

Pa.  Europe,  Asia,  Australia,  So.  America. 

The  type  with  dimensions  about  one-fifth  tr  one-fourth  larger, 
and  with  oogonia  more  generally  patent,  is  found  only  in 
Europe.  B.  dumosa  Wood,  1872,  p.  202,  PI.  XVIII,  fig.  6,  ac- 
cording to  Hirn  should  be  included  in  this  variety. 

16.  B.    RECTANGULARIS    Wittrock,    1870,    p.    142 ;    Wolle, 
1887,  p.  102,  PL  XC,  fig.  i  ;   Hirn,    1900,  p.  359,   PI.   LX,  fig. 
376;  P.  B.-A.,  No.   516.     Dioecious,   nannandrous,    gynandro- 
sporous; little  branched,  branches  often  very  long  ;  vegetative 
cells  in  cross  section  subrectangular  ;  oogonia  ellipsoid,  patent 
or  more  rarely  erect,  below  terminal  setae  or  androsporangia, 
more  rarely  vegetative  cells  ;  androsporangia  scattered  or  epigy- 
nous, i-?-celled  ;  dwarf  males    near   oogonium  or  more  rarely 
on  it  ;  antheridium  exterior,  i-4-celled. 


274          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

veg.  cell,  16-23  fj.  diam.,  i%-2    diam.  long, 

oog.,  3!-39M      "  45-63  M  long, 

andr.  cell,  13-16  M      "  10-27  /"•     " 

nan.  stipe,  14-18  n      "  22-27  /"•     " 

anth.  cell,  8-10  /u,      "  5-7    M     " 

Mass.,  R.  I.,  Conn.,  Pa.  Europe. 

Var.  HILOENSIS  Nordstedt,  1878,  p.  22;  Wolle,  1887,  p.  102, 
PI.  XC,  figs.  2-3 ;  Him,  1900,  p.  361,  PI.  LX,  fig.  377.  Smaller, 
vegetative  cells  longer,  androsporangia  generally  epigynous, 
more  rarely  scattered. 

veg.  cell,  14-19  ju.  diam.,  i%-2l/2  diam.  long, 

oog.,  28-32 /x      "  47-51    /xlong. 

andr.  cell,  12-14/11      "  13-16    /u.     " 

nan.  stipe,  13-14  /"•      "  22-24    M     " 

anth.  cell,  8-9    M      "  5-7^" 

Australia. 
Wolle's  reference  is  the  only  American  report. 

B.  rectangularis  and  B.  varians  resemble  each  other  consider- 
ably, but  the  latter  is  more  branched  and  has  shorter  cells. 

17.  B.  REPANDA  Wittrock,  1874,  p.  55  ;  Wolle,  1887,  p.  102, 
PI.  XC,  fig.  4  ;  Him,  1900,  p.  363,  PI.  L,XI,  fig.  380  ;  P.  B.-A., 
No.  814;  B.  rhadinospora  Wolle,   1887,  p.   103,   PI.  LXXXIX, 
figs.    4    and    5.       Dioecious,    nannandrous,    gynandrosporous ; 
oogonia   suboblong-ellipsoid,   patent  or  erect,  below  androspo- 
rangia,   terminal    setae  or    vegetative    cells  ;    androsporangia 
epigynous  or  subepigynous,  i-?-celled;  dwarf  males  near  or  on 
oogonium ;    antheridium  exterior,    i-3-celled ;    vegetative  cells 
sometimes  repand. 

veg.  cell,  12-17  M  diam.,  2~3/^  diam  long, 

oog.,  26-36  n      "  43-58    M  long, 

andr.  cell,  ,13-15  M      "  16-21    n     " 

nan.  stipe,  11-15  M      "  21-27    /u.     " 
anth.  cell,                     7-10  ^      "  5-7      /x     " 

Greenland,  Mass.,  Me.,  N.  J.,  Fla.  Europe, 

18.  B.  INSIGNIS  Pringsheim,    1858,  p.   73,   PI.  VI,   fig.   7  ; 
Wolle,  1887,  p.  101,  PI.  LXXXVIII,  figs.  2  and  3  ;   Him,  1900, 
p.  364,  PL  LXII,  fig.  383;  P.  B.-A.,  Nos.    1332,    1430.     Dioe- 
cious, nannandrous,  gynandrosporous ;  oogonia  ellipsoid,  erect 
or  patent,  below  androsporangia,   terminal  setae  or  vegetative 
cells ;  androsporangia  epigynous  or  subepigynous,  more  rarely 
scattered,  i-?-celled  ;  dwarf  males  near  or  on  oogonium  ;  anther- 
ididium  exterior,  i-3-celled. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  275 

veg.  cell,  J9-25  Mdiam.,  2^-3^  diaiu.  long. 

oog.,  46-56  /x      "  70-90    M  long. 

andr.  cell,  16-20/4      "  9-25    fj.     " 

nan.  stipe,  16-19/01      "  29-33    v-    " 

anth.  cell,  10-13  M      "  7-10    /j.     " 

Mass.,  N.  J.,  Alaska.  /Europe,  Australia. 

Var.  RETICULATA  (Nordst.)  Him,  1900,  p.  365,  PI.  L,XII, 
fig.  384.  Epispore  reticulate-denticulate,  with  doubly  dentate 
longitudinal  ridges,  the  teeth  united  to  each  other  by  transverse 
ridges ;  the  longitudinal  ridges  more  or  less  wavy  and  crooked, 
sometimes  anastomosing  ;  dimensions  about  the  same  as  in  the 
type. 

The  netted  surface  above  described  is  sometimes  found,  bu 
exceptionally  and  in  less  degree,  on  oospores  of  the  type ;  the 
variety  merely  has  it  more  marked  and  more  generally. 
Mass.  Europe. 

19.  B.  MINOR  A.  Braun  in  Kiitzing,  1849,  p.  422;  Wolle, 
1887,  p.  101,  PI.  LXXXVII,  fig.  7;  Him,  1900,  p.  369,  PI. 
LXIII,  fig.  390.  Dioecious,  nannandrous,  gynandrosporous ; 
oogonia  suboblong-ellipsoid,  erect  or  more  rarely  patent,  below 
terminal  setae,  androsporangia,  or  more  rarely  vegetative  cells; 
anclrosporangia  epigynous,  subepigynousor  scattered,  i-?-celled  ; 
dwarf  males  near  or  on  the  oogoniurn  ;  antheridium  exterior, 
i-4-celled. 

veg.  cell,  18-25  |U  diam.,  1^-2     diam.  long. 

oog.,  32-42  M      "  59-69  Mlong. 

andr.  cell,  15-16  M      "  16-21   /u     " 

nan.  stipe,  12-15  M      "  22-24  fi    " 

anth.  cell,  6-10  M      "  6-7     M     " 

N.  J.  Sweden. 

Family  6.     CHAETOPHORACEAE. 

Fronds  filamentous,  except  in  a  few  doubtful  forms,  usually 
much  branched,  sometimes  united  in  disk-like  expansions  ;  cells 
uninucleate,  with  band-  or  disk-shaped  chromatophore,  often 
somewhat  divided  or  with  projections  ;  with  one,  rarely  more 
pyrenoids  ;  hairs  almost  always  present,  but  varying  in  charac- 
ter ;  asexual  reproduction  by  4-ciliate,  in  some  cases  biciliate 
zoospores,  by  aplanospores,  akinetes,  and  with  special  Palmella 
and  Schizomeris  stages  in  many  genera  ;  sexual  reproduction 
in  many  genera  by  gametes  similar  to  the  zoospores. 

This  family  includes  both  fresh  water  and  marine  forms,  but 
the  larger  part  is  fresh  water.  There  is  a  great  range  in  differ- 
entiation between  the  extreme  forms,  and  some  forms  are  in- 


276     •      TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

eluded  here  which  have  little  resemblance  to  the  more  typical 
genera,  but  for  which  no  more  appropriate  place  could  be  found. 

KEY  TO  THE  GENERA  OF  CHAETOPHORACEAE. 

i.     Fronds  erect  with  differentiated  base  and  apex.  2. 

i.     Fronds  creeping  or  expanded,  no  differentiated  base  and  apex.     5. 
2.     Fronds  less  than  i  mm.  high,  tips  not  acute  nor  setiferous. 

22.       MlCROTHAMNION. 

2.     Fronds  larger,  tips  generally  acute  or  setiferous.  3. 

3.     Filaments  united  in  gelatinous  thalli  of  definite  form. 

23.     CHAETOPHORA.     • 

3.     Filaments  practically  free.  4. 

4.     Fascicled  ramuli  different  in  character  from  stem. 

25.     DRAPARNAI,DIA. 
4.     Stem,  branches  and  ramuli  little  differentiated. 

24.    STIGEOCI.ONIUM. 
5.     Filaments   originally    creeping,    producing     short,    erect    branches, 

closely  packed  into  a  thin  layer.  6. 

5.     No  dense  layer  of  vertical  filaments  distinct  from  basal  layer.        8. 

6.     Fresh  water.  7. 

6.     Marine.  21.     PIUNIA. 

7.     Cells  of  filaments  seldom  over  10  /n  diam.;    sporangia  little  if  an}7 

larger  than  vegetative  cells.  20.     CHXOROTYUUM. 

7.     Cells  of  filaments  seldom  under  20  M  diam.;  fructification  in  swollen 

terminal  cells.  19.     GONGROSIRA. 

8.     Filaments  more  or  less  united  laterally.  9. 

8.     Filaments  not  united.  18. 

9.     Forming  an  irregular  loose  incrustation.     9.    PSEUDENDOCLONIUM. 

9.     Forming  a  definite  disk.  10. 

10.     Disk  mouostromatic.  n. 

10.     Disk  polystromatic.  14. 

ii.     Setae  or  hairs  more  or  less  abundant.  12. 

ii.     No  setae  or  hairs.  13. 

12.     Radiating  filaments  turning  up  at  the  end.     10.    ENDOCLOXIUM. 

12.     Radiating  filaments  not  turning  up  at  the  end. 

15.     OCHLOCHAETE. 
13.     Disk  formed  by  filaments  radiating  from  a  center. 

14.     PRINGSHEIMIA. 
13.     Disk  formed  by  the  union  of  irregular  filaments. 

13.      EPICIyADIA. 

14.     Setae  or  hairs  present.  16. 

14.  No  setae  or  hairs.  15. 

15.  On  shells  of  turtles.  ii.  DERMATOPHYTON. 

15.  On  algae,  stones,  etc.;  marine.  12.  Ui/vEl.ivA. 

16.     Hairs  gelatinous.  16.     CHAETOPELTIS. 

16.     Setae  not  gelatinous.  17. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  277 

17.     Setae  articulate.  18.     ARTHROCHAETE. 

17.     Setae  inarticulate.  17.     CHAETOBOLUS. 

18.    Cells  solitary.  i.    DIPLOCHAETK. 

18.     Cells  united  in  filaments.  19. 

19.     Epiphytic  or  in  loose  tissue  of  other  algae.  20. 

19.     Living  in  the  membrane  of  other  algae  or  in  outer  coating  of  mol- 
lusks.  24. 

20.     Fresh  water.  4.     CHAETOSPHAERIDU-M. 

20.     Marine.  21. 

21.     Setae  present.  22. 

21.     No  setae.  23. 

22.     Setae  arising  from  the  ends  of  upright  cells.     5.     ACROCHAETE. 

22.     Setae  arising  from  small  special  cells.  8.     BoLBOcoivEON. 

23.     Basal  network  with  short  vertical  branches.     7.    PSEUDOPICTYON. 
23.     Branching  irregular,  no  definite  network.  6.     ENDOPHYTON. 

24.     In  cell  wall  of  algae.  2.     ENDODERMA. 

24.     In  outer  coating  of  mollusk  shells.  3.     TELLAMIA. 

In  addition  to  the  genera  given  in  the  foregoing  key,  there 
are  a  few  others  which  may  be  reduced  or  rudimentary  forms 
belonging  to  this  family ;  the  cells  have  the  same  structure, 
some  species  at  least  produce  zoospores  and  aplanospores,  and 
all  have  regular  vegetative  cell-division  ;  there  seems  to  be  no 
better  place  for  them, 
i.  Cells  in  older  plants  borne  on  stalks  formed  from  the  cell  wall. 

27.     UROCOCCUS. 
i.     Cells  never  stalked.  2. 

2.     Cells  dividing  and  soon  separating,   or  forming  small   irregular 
masses  or  short  filaments.  26.     PLEUROCOCCUS. 

2.     Cell  wall  persisting  and  enclosing  walls  of  later  generations.     3. 
3.     Division  in  one  direction.  28.     DACTYLOTHECE. 

3.     Division  in  two  or  three  directions.  4. 

4.     Families  encircled  by  one  or  more  opaque  bands. 

31.  GLOEOTAENIUM. 
4.     No  opaque  bands.  5. 

5.     Families  spherical  or  irregular.  6. 

5.     Families  united  into  subcylindrical,  branching  thalli. 

32.  PALMODICTYON. 
6.     Families  enclosed  in  a  spherical,  gelatinous  envelop. 

30.     GLOIOCOCCUS. 
6.     Families  with  no  general  envelop.  29.     GLOEOCYSTIS. 

i.     DIPLOCHAETE  Collins,  1901,  p.  242. 

Cells  solitary  or  a  few  united  into  a  gelatinous,  subfilamen- 
tous  series,  globose,  flattened,  ellipsoid  or  ovoid,  furnished  with 


278  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

two   or   more    long,   simple,    sheathless  setae ;    chromatophore 
single,  parietal  (with  pyreuoid?).     Reproduction  unknown. 

D.  SOLITARIA  Collins,  1901,  p.  242.  Epiphytic  ;  cells  25-30/11 
diatn.,  with  wall  5-8  /u,  thick,  little  or  not  at  all  lamellose  ;  setae 
two,  arising  from  the  lower  half  of  the  cell,  usually  opposite, 
straight,  tapering,  4-6  p.  thick  at  base.  Fig.  99.  On  Laurencia 
obtusa,  Jamaica. 

W.  and  G.  S.  West  published,  1903,  p.  79,  Polychaetophora 
gen.  n.  Thallus  minute,  of  few  cells,  filamentous,  or  some- 
times unicellular;  cells  subglobose,  ellipsoid  or  ovoid,  mem- 
brane very  thick  and  strongly  lamellate  ;  each  cell  furnished 
with  8-12  long,  flexuous,  simple,  sheathless  setae;  chromato- 
phore single,  parietal,  often  indistinct  (with  one  pyrenoid?). 
P.  Ictonejlosa  sp.  unica,  PI.  CCCCXI/VIII,  figs.  1-4.  Characters 
of  the. genus.  This  seems  to  be  quite  distinct  from  Diplochaete ', 
but  G.  S.  .West;  1908,  p.  279,  PI.  XX,  figs.  1-6,  published  Poly- 
chaclophora  simplex  sp.  n.  Cells  subglobose  or  ovoid,  membrane 
thin  and  homogeneous  ;  dorsal  part  of  each  cell  furnished  with 
2-4  long,  flexuous,  simple,  sheathless  setae.  If  the  genus  be 
extended  so  as  to  include  this  species,  it  would  certainly  include 
Diplochaete  splitaria,  and  as  the  genus  Diplochaete  has  priority, 
that  name  must  be  used.  It  is  unfortunate  that  a  more  appro- 
priate name  should  have  to  give  place  to  one  less  appropriate  to 
most  of  the  species,  but  there  seems  to  be  no  other  course  avail- 
able than  to  revise  the  original  description  of  Diplochaete,  and  to 
include  the* two  British  species  of  the  Wests  as  D.  lamellosa 
(W.  and  G.  S.  West)  Collins  nov.  comb.,  and  D.  simplex  (G.  S. 
West)  Collins  nov.  comb. 

2.     ENDODERMA  L/agerheim,  1883,  p.  74. 

Frond  microscopic,  creeping  on  or  within  other  algae  or 
aquatic  plants  ;  filaments  irregularly  branched,  with  or  without 
hairs ;  cell  division  mostly  terminal ;  chromatophore  a  parietal 
layer  with  one  or  more  pyrenoids  ;  zoospores  2-4-ciliate,  with 
stigma,  formed  4  or  more  in  a  cell,  escaping  by  a  hole  and  soon 
germinating  ;  asexual  reproduction  by  biciliate  zoogametes 
without  stigma  is  probable,  but  not  certain. 

A  genus  of  a  few  species,  marine  and  fresh  water  ;  ours  all 
with  one  pyrenoid  and  without  hairs. 


THE  GREEN  AI<GAE  OF  NORTH  AMERICA  279 

KEY  TO  THE  SPECIES  OF  ENDODERMA. 

i.     Endophytic,  marine.  2. 

i.     Epiphytic,  fresh  water.  4. 

2.     In  leaves  of  Zostera.  3.     E.  perforans. 

2.     In  marine  algae.  3. 

3.     Cells  averaging  9  ,u  diam.,  cylindrical,  i.     E.  Wittrockii. 

3.     Cells  averaging  6  ,u  diam.,  irregular.  2.     E.viride. 

4.     Cells  subglobose  to  ellipsoid.  4.     E.  Pithophorae. 

4.     Cells  much  flattened.  5.     E.  polyinorp hunt. 

1.  E.  WITTROCKII  (Wille)  Lagerheim,  1883,  p.  75  ;  Hazen, 
1902,  p.  226,  PI.  XLII,  fig.  i  ;  P.  B.-A.,  Nos.  265,  1469.     Fila- 
ments  simple    or    irregularly    branched,    with   tapering   ends ; 
branches  sometimes  united  laterally  ;  cells  cylindrical,  5-10  /x, 
usually  9  //.diam.,  i-i}4  diam.  long,  with  one  pyrenoid  ;  growing 
in  the  cell  walls  of  brown,  less  commonly  of  red  algae  ;  repro- 
duction little  known.     Fig.  100.     Me.  to  Conn.  Europe. 

Probably  common  in  summer  and  autumn,  but  easily  over- 
looked, as  there  is  seldom  anything  in  the  appearance  of  the 
host  to  indicate  the  presence  of  the  endophyte.  It  has  been 
found  most  frequently  in  Elachista  furicola,  but  occurs  in  other 
algae  ;  at  times  it  is  quite  common  in  Desmotrichum  undulation . 

2.  E.  VIRIDE  (Reinke)  Lagerheim,  1883,  p.  74  ;  Entocladia 
vindis  Reinke,  1879,  p.  476,  PI.  VI.       Filaments  usually  much 
branched,  3-8  /A,  usually  6  //.  diam.,  cells  1-6  diam.  long,  some- 
times cylindrical,  oftener  irregularly  swollen  and  contorted,  with 
one  pyrenoid  ;  terminal  cell  blunt  or  tapering  ;  growing  in  cell 
walls  of  various  algae.     Mass.  Europe. 

A  smaller  plant  than  the  preceding,  and  with  more  irregular 
branching.  In  Europe  it  has  a  more  southern  range  than  E. 
Wittrockii,  and  it  .is  to  be  expected  in  localities  south  of  Cape 
Cod. 

3.  E.  PERFORANS  Huber,  1892,  p.  316,  PI.  XIV.    Filaments 
3-5  p.  diam.,  endophytic  in  the  dead  leaves  of  Zostera  marina  ; 
cells  more  or  less  irregular  in  form  and  of  varying  length,  with 
one  pyrenoid  ;  larger,  rounded  cells  formed  here  and  there,  up 
to  14  p.  diam;  asexual  reproduction  by  ovoid  or  subspherical 
4-ciliate  zoospores  with  stigma,  formed  in  the  larger  cells,  8  in 
a  cell.     Me.,  Mass.  Europe. 

The  slender  filaments  creep  among  the  epidermis  cells  of  the 
host,  while  the  larger  cells  and  sporangia  are  formed  within  the 
large  cells  of  the  inner  layer  of  the  Zostera.  The  zoospore 
comes  to  rest  on  the  surface  of  a  Zostera  leaf  and  emits  a  tube 


28o          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

which  penetrates  th.e  outer  layer  of  the  host,  and  begins  to 
branch  almost  immediately.  The  species  is  probably  to  be 
found  everywhere  in  the  dead  and  faded  Zostera  leaves  in  marsh 
pools. 

4.  E-   PITHOPHORAE  West,    1905,  p.  283.     Epiphytic  ;  fila- 
ments not  over  200  /ulong,  irregularly  branched,  branches  atten- 
uate, more  or  less  concrete  ;  cells  25-38  //.  diam.,  subglobose, 
ellipsoid,  ovoid,  or  oblong  ;  apical  cell  10-16  p.  diam.  ;  cell  with 
one  pyrenoid,  membrane  3-4  /x  thick.     Barbados. 

This  species  was  found  growing  on  Pithophora  Cleveana,  on  or 
in  the  immediate  vicinity  of  the  intercalary  spores  ;  like  the 
following  species  it  is  not  at  all  endophytic,  and  thus  connects 
Endoderma  with  Epicladia,  but  the  filaments  do  not  unite  to  form 
a  definite  disk. 

5.  E.  POLYMORPHUM  West,  1905,  p.  283,  PI.  CCCCLXIV, 
fig.    19.     Epiphytic ;    filaments    up   to   250  /x  long,    irregularly 
branching   and  anastomosing;    cells  flattened,   polymorphous, 
very  irregular  in  form,    15-39X6-20  /u ;  thickness  of  membrane 
3-7-5  P- ',  cell  with  one  pyrenoid.     Barbados. 

This  species  occurs  on  the  same  host  as  E,  Pithophorae,  but 
on  vegetative  cells  only  ;  the  flattened  cells,  with  very  irregular 
outline,  seem  to  distinguish  it  from  its  companion. 

3.     TELLAMIA  Batters,  1895,  p.  315. 

Frond  of  radiating,  irregularly  branched  filaments,  creeping 
in  the  periostracum  of  mollusca  ;  parietal  chromatophore  nearly 
filling  the  cell,  with  one  pyrenoid  ;  cells  often  swollen  ;  asexual 
reproduction  by  zoospores,  formed  in  slightly  swollen  cells. 

The  two  known  species  occur  often  in  company,  in  the  outer 
skin  of  the  shells  of  lyittorina,  forming  a  more  or  less  dense  net- 
work, but  not  penetrating  the  shell  itself.  The  color  of  the 
shells  they  inhabit  is  changed  from  bright  yellow  to  some  shade 
of  dull  yellow  or  brown. 

T.  CONTORTA  Batters,  1895,  p.  316,  PI.  XI,  figs.  18-24. 
Filaments  yellowish  green  or  brown,  densely  and  irregularly 
branched;  cells  6-9X3-10  p.,  ovoid  or  ellipsoid;  branching  of 
two  kinds,  horizontal,  similar  to  the  main  filament,  branches 
sometimes  falcate  or  coiled,  often  anastomosing  ;  vertical, 
branches  short,  often  united  laterally,  with  acute  terminal  cells ; 
inflated  cells,  up  to  20  /u.  diam.,  occasionally  occurring  in  the 
horizontal  branches.  Figs,  in,  112.  On  Littorina  palliata 
Gould.  Southern  Mass.  England. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  281 

The  irregularly  and  densely  branched-  fronds  form  an  open 
or  almost  continuous  layer  in  the  membrane,  sending  short 
branches  up  and  down,  to  the  outer  surface  of  the  membrane, 
or  to  the  surface  of  the  shell.  In  England  it  is  generally  ac- 
companied by  the  other  species,  T,  infricafa  Batters,  with  more 
cylindrical  cells  and  looser  branching  ;  this  species  has  not  yet 
been  noticed  in  this  country. 

4.  CHAETOSPHAERIDIUM  Klebahn,  1891,  p.  7. 
Frond  microscopic,  epiphytic  on  various  algae  ;  cells  globose 
or  hemispherical,  with  disk-shaped  chromatophore  and  one  py- 
renoid,  bearing  above  a  very  long,  delicate  sheathed  hair  ;  cells 
dividing  by  a  horizontal  wall,  the  daughter  cell  then  passing  to 
the  side  of  the  mother  cell,  or  emitting  a  tubular  projection,  at 
the  end  of  which  is  formed  a  new  setiferous  cell ;  reproduction 
by  motile  spores,  but  character  and  development  unknown. 
When  a  setiferous  cell  has  divided  and  formed  a  tube,  the  con- 
tents of  the  lower  (daughter)  cell  passes  through  the  tube  to  the 
new  cell;  the  tube  either  disappears  as  in  C.  globositw,  or  re- 
mains an  empty  utricle  as  in  C.  Pringsheimii. 

KEY  TO  'THE  SPECIES  OF  CHAETOSPHAERIDIUM. 
i.     Utricles  short  and  evanescent;  general  gelatinous  envelop  present. 

i.     C.  globosum. 
i.     Utricles  well  developed  ;  no  general  gelatinous  envelop. 

2.     C.  Pringsheimii. 

1.  C.  GLOBOSUM  (Nordst.)  Klebahn,  1893,  p.  306,  PI.  XIV, 
figs.  5-io;    Hazen,  1902,  p.   229;   Aphanochaetc  globosa  Wolle, 
1887,  p.  119,  PI.  CV,  fig.  5.     Cells  12-18  n  diam.,  sheath  16-17  p. 
long,  2-3  /u.  diam.  ;  cells  closely  set,  utricles  inconspicuous,  gen- 
eral gelatinous  coating  ample.     On  algae,  chiefly  Oedogonium. 
N.  H.  to  N.  J.,  Neb.  Europe. 

2.  C.  PRINGSHEIMII   Klebahn,    1891,   p.   7;    1892,  p.  268,- 
PL  IV.     Cells  9-12  p.  diam.,  sheaths  13-18  /*  long,  about  2  p. 
diam.  ;   cells  united  by  well  developed,  persistent  utricles  into 
creeping   filaments,    sometimes   with    erect   ends  ;    no   general 
gelatinous   coating.     On  algae,   chiefly  Colcochactc.     Fig.    104. 
Canada,  near  Lake  Superior.  Europe. 

There  may  be  some  doubt  whether  the  plant  figured  by  Hazen, 
1902,  PI.  XLII,  figs.  3  and  4,  is  really  C.  Pringsheimii,  as 
stated,  or  a  form  of  C.  globoswn  ;  a  comparison  of  this  plate  with 
Klebahn's  plate  would  seem  to  indicate  that  they  were  not  the 
same  species. 


282  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

5.  ACROCHAETE  Pringsheim,  1862,  p.  i. 
Epiphytic  or  endophytic ;  filaments  creeping,  branching,  artic- 
ulate, bearing  short  erect  branches,  which  often  end  in  a  slender 
tube  containing  a  long,  slender  seta  ;  chromatophore  parietal, 
with  one  or  more  pyrenoids ;  sporangia  formed  from  terminal 
cells  of  erect  branches,  bearing  no  setae,  producing  many  bicili- 
ate   zoospores,  which  germinate  to  produce  the   parent    form  ; 
sexual  reproduction  reported,  but  uncertain.     Marine. 

KEY  TO  THE  SPECIES  OF  ACROCHAETE. 

i.     Cells  seldom  2  diam.  long.  2.  A.  parasitica. 

i.     Cells  longer,  2-6  diam.  i.     A.  repens. 

1.  A.   REPENS  Pringsheim,    1862,  p.   2,   PL    II;    P.   B.-A., 
No.  1279.     Creeping  filaments  7-9  p.  diam.,  cells  2-6  diam.  long, 
usually  with  several  pyrenoids;  sporangia  elongate-ovoid,  8-12 
X  20-40  /A.     Fig.   101.     In  the  cortical  layer  of   Chorda  filum, 
Laminaria,  etc.     Mass.  Europe. 

The  setae  are  sometimes  very  abundant  in  this  species,  some- 
times so  rare  that  a  careful  examination  is  needed  to  find  any. 

2.  A.  PARASITICA  Oltmanns,  1894,  p.  208,  PI.  VII,  figs,  i- 
10  ;  Rosenvinge,  1898,  p.  114.     Creeping  filaments  8-12  it  diam., 
cells  about  i^  diam.  long,  with  disk-shaped  chromatophore  and 
one  pyrenoid  ;  sporangia  somewhat  clavate,  usually  projecting 
above  the  surface  of  the  host  plant,  about  25X10-12  p..     In  old 
fronds  of  Fucus.     Greenland.  Europe. 

6.  ENDOPHYTON  Gardner,  1909,  p.  371. 
Filaments  endophytic  in  red  algae,  sparingly  and  irregularly 

branched  in  the  medulla  of  the  host,  more  freely  near  the  sur- 
face ;  cells  with  band-shaped  chromatophore  and  one  pyrenoid  ; 
sporangia  at  the  surface  of  the  host,  on  short  erect  branches, 
producing  pyriform,  biciliate  zoospores. 

E.  RAMOSUM  Gardner,  1909,  p.  372,  PI.  XIV,  figs.  3  and  4. 
Filaments  4-6  it  diam.,  often  tortuous  and  irregular,  cells  6-8 
diam.  long;  sporangia  clavate,  10-12  //.  diam.,  pointed  when 
young  ;  zoospores  numerous,  3  /x  diam.,  escaping  by  an  opening 
at  the  end  of  the  sporangium.  Fig.  121.  In  fronds  of  Iridaea 
laminaroides  Bory,  Gigartina  radula  (Esper)J.  Ag.  Cal. 

Forming  patches  usually  a  few  mm.  diam.,  but  which  may  be 
confluent  and  cover  considerable  areas,  usually  near  the  base 
of  the  frond  of  the  host.  In  Gigartina  the  patches  show  more 
reddish  than  the  rest  of  the  frond. 

7.     PSEUDODICTYON  Gardner,  1909,  p.  374. 

Filaments  endophytic  in  larger  algae,  much  branched,  long 


THE  GREEN  ALGAE  or  NORTH  AMERICA  283 

and  tortuous,  the  branches  at  right  angles,  forming  a  network 
among  the  cells  of  the  host.;  short  branches  arising  from  the 
cells  of  the  network,  the  terminal  cell  of  each  branch  develop- 
ing into  a  sporangium  at  the  surface  of  the  host.  Cells  with 
parietal  chromatophore  and  one  large  pyrenoid. 

Evidently  nearly  related  to  1'lndophyton,  but  there  is  a  sharper 
differentiation  between  the  two  parts  of  the  frond,  the  definite 
horizontal  network,  and  the  short  fruiting  branches.  The  net- 
work has  a  superficial  resemblance  to  Microdictyon,  but  the  re- 
semblance is  probably  only  superficial. 

P.  GENICULATUM  Gardner,  1909,  p.  374,  PI.  XIV,  figs.  5  and 
6.  Young  cells  3-4  /*  diam.,  becoming  larger  with  age  ;  vertical 
branches  of  2-3  cells  arising  from  practically  all  the  cells  of  the 
network;  sporangia  8-12  p.  diam.  Fig.  120.  In  the  cortical 
layer  of  Laminaria  Sinclair ii,  near  San  Francisco,  Cal. 

The  patent  branches  of  the  main  filaments  usually  reach  to  a 
neighboring  filament,  thus  forming  a  network  with  subrec- 
tangular  meshes,  each  enclosing  4-8  cells  of  the  host ;  from  this 
network  arise  vertically  short  branches  reaching  to  the  surface 
of  the  host  and  terminating  in  sporangia  with  rounded  ends  ; 
the  nature  of  the  reproductive  bodies  formed  in  these  sporangia 
is  not  known.  The  plant  is  found  chiefly  in  the  terminal  part 
of  the  blade  of  the  host. 

8.     BOLBOCOLEON  Pringsheim,  1862,  p.  i. 

Frond  microscopic,  epi-  or  endophytic  in  various  algae  ;  fila- 
ments creeping,  branching,  consisting  of  irregular  rounded 
cells,  on  the  upper  (outer)  side  of  which  are  borne  smaller  bulb- 
shaped  cells,  prolonged  into  a  tube,  from  which  projects  a  long, 
slender  hair  ;  chromatophore  in  the  filament  cells  a  parietal  per- 
forate layer  with  5-10  pyrenoids ;  in  the  piliferous  cells  an 
irregularly  toothed  plate  with  two  pyrenoids.  Reproduction  by 
biciliate  zoospores,  produced  in  large  numbers  in  the  filament 
cells ;  whether  sexual  or  asexual  is  not  known.  Only  one 
species. 

B.  PIUFERUM  Pringsheim,  1862,  p.  8,  PI.  I;  Farlow,  1881, 
p.  57;  Hazen,  1902,  p.  227;  P.  B.-A.,  No.  1225.  Vegetative 
cells  12-16  p.  diam.,  2-3  diam.  long.  Fig.  108.  Newfoundland 
to  R.  I.;  California.  Europe. 

Not  uncommon  in  summer  and  autumn  in  various  loose- 
tissued  marine  algae,  seldom  in  such  quantity  as  to  be  noticeable 
without  microscopic  examination,  but  occasionally  occurring  in 


284  TUFTS  COLLEGE  STUDIES,  Voi,.  II,  No.  3 

such  quantity  as  to  give  a  whitish  appearance  to  algae  normally 
brown.  The  circumstances  favorable  to  its  development  favor 
also  other  small  epiphytes,  and  it  is  usually  accompanied  by 
Calothrix  parasitica,  Streblonema  species,  etc.  It  is  usually 
found  in  brown  algae,  Leathesia  difformis,  Castagnca  virescens, 
Mesogloia  divaricata,  Ralfsia  Borneti,  etc.  ;  sometimes  in  old 
plants  of  Dictyosiphon  and  Scytosiphon,  where  the  normally  com- 
pact cortical  layer  has  become  loose  ;  occasionally  in  red  algae 
such  as  Nemalion  rmdtifidum  and  N.  Andersonii. 

9.       PSEUDENDOCLONIUM  Wille,    IQOI,  p.   29 

Frond  of  much  and  irregularly  branched  filaments,  packed  to- 
gether in  an  irregular  layer,  with  short,  erect  branches,  and 
with  very  short  rhizoids  ;  cells  of  irregularly  rounded  shape ; 
chromatophore  a  small  parietal  disk  with  one  pyrenoid.  Asexual 
reproduction  by  akinetes,  and  by  4-ciliate  zoospores  without 
stigma. 

Only  one  species. 

P.  SUBMARINUM  Wille,  1901,  p.  29,  PL  III,  figs.  101-134; 
P.  B.-A.,  No.  1124.  Cells  6-7  &  diam.,  forming  a  pseudopar- 
enchymatous  layer  on  the  surface  of  and  penetrating  more  or 
less  into  the  substance  of  woodwork,  near  high  water  mark  ; 
akinetes  of  two  types,  one  with  wall  little  thickened,  germinat- 
ing at  once  ;  the  other  with  thick  walls  and  remaining  in  the 
resting  state  for  some  time  ;  zoosporangia  slightly  larger  than 
the  vegetative  cells,  producing  each  4-8  4-ciliate  zoospores, 
about  4  i*.  diam.,  escaping  by  a  short  neck;  germinating  im- 
mediately. Fig.  87.  Me.,  Mass.,  R.  I.  Europe. 

This  species  forms  a  fine  green  granular  coating  on  shaded 
woodwork  near  high  water  mark,  and  in  appearance  much  re- 
sembles the  common  Pleurococcus  vtilgaris  ;  but  is  distinctly  fila- 
mentous, and  appears  to  be  a  reduced  form  belonging  to  the 
Chaetophoraceae . 

10.     ENDOCLONIUM  Szymanski,  1878,  p.  18. 

Frond  endo-  or  epiphytic,  forming  larger  or  smaller  disks, 
filaments  erect  at  the  margin,  and  here  and  there  in  the  disk, 
forming  erect,  branching  tufts.  Asexual  reproduction  by  akin- 
etes, and  by  small  biciliate  and  larger  4-ciliate  zoospores,  with 
red  stigma,  formed  one  to  several  in  a  cell  ;  sexual  reproduction 
by  small  biciliate  gametes. 

A  genus  of  minute  plants  inhabiting  the  leaves  of  various 
aquatic  plants,  probably  closely  allied  to  Stigfoclonhim.  We 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  285 

have  only  one  species,  and  that  somewhat  doubtful,  details  of 
development  and  reproduction  being  insufficiently  known. 

E.  ?  MOEBIUSIANUM  De  Toni,  1889,  p.  208  ;  Stigeodonium  sp., 
Mobius,  1888,  p.  239,  PI.  IX,  fig.  3.  Disk  up  to  500  \t.  diam., 
composed  of  filaments  radiating  irom  a  common  center  ;  cells  5  ^ 
diam.,  1-2  diam.  long;  rising  above  into  a  short,  papilla-like 
extension ;  occasionally  seta-bearing.  Fig.  88.  Porto  Rico. 

The  erect  filaments  are  much  less  developed  than  in  most 
species  of  the  genus  ;  Mobius'  first  supposition  may  be  correct, 
that  it  is  a  species  or  state  of  growth  of  Stigeodonium. 

ii.  DERMATOPHYTON  Peter,  1886,  p.  191. 
Forming  rounded  or  irregular  disks,  on  the  shells  of  turtles, 
of  closely  packed  cells  in  several  layers,  below  sending  cunei- 
form projections  into  the  shell ;  asexual  reproduction  by  (bicili- 
ate  ?)  zoospores  formed  by  repeated  division  of  the  contents  of 
the  enlarged  cells  of  the  outer  layer. 

Only  one  species. 

D.  RADIANS  Peter  1886,  p.  191  ;  D.  radicans  Potter,  1887, 
p.  251,  PI.  VIII.  Disks  up  to  12  mm.  diam.,  composed  of 
squarish  cells,  originally  in  branching  radial  series,  but  soon 
united  to  a  parenchymatous  layer,  several  cells  thick,  except  at 
the  margin  ;  the  superficial  cells  enlarging  to  form  sporangia, 
from  which  the  contents  are  discharged  in  the  form  of  zoospores, 
the  cells  below  then  becoming  sporangia,  the  thickness  of  the 
frond  being  maintained  by  successive  divisions  of  the  cells  by 
horizontal  planes.  Fig.  93.  Mass.  Europe. 

The  name  is  wrongly  quoted  by  Potter  as  D.  radicans,  and  the 
error  has  been  copied  by  De  Toni,  1889,  Wille,  1900,  and 
others ;  no  one  seems  to  have  taken  the  trouble  to  look  up  the 
original  description'. 

12.     ULVELLA  Crouan,  1859,  p.  288. 

Fronds  forming  small  disks  on  larger  plants  or  other  objects, 
firmly  attached  by  the  under  surface,  originally  monostromatic, 
of  radiating,  laterally  united,  dichotomous  filaments ;  later 
polystromatic,  except  at  the  margin  ;  cells  with  parietal  chro- 
matophore  and  one  pyrenoid,  arranged  in  more  or  less  definite 
vertical  series  ;  biciliate  zoospores  formed  in  the  central  cells, 
4-8-16  in  a  cell,  escaping  by  an  opening  at  the  top.  Marine. 

KEY  TO  THE  SPECIES  OF  ULVELLA. 

i.     On  stones  and  shells.  3.     U.  lens. 

I.     On  algae.  2. 


286  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

2.     Strictly  epiphytic.  4.     U.  prostrata. 

2.  Penetrating  the  host  more  or  less.  3. 

3.  Gelatinous,  up  to  75  /JL  thick,  not  confluent.  2.  U.fucicola. 

3.  Not  gelatinous,  up  to  250  M  thick,  confluent,  i.  U.  confine  us. 

1.  U.  CONFLUENS  Rosenvinge,  1893,  p.  924,  fig.  39.     Form- 
ing green,   confluent  incrustations  on  old  stipes  of  Laminaria 
longicruris ;  when   mature,    to   250  ^  thick,  smooth,   composed 
of    more   or    less   regular,    closely    united,    vertical    filaments, 
diverging  towards  the  margin;  cells  10-12  //.  diam.,  2-4  diam. 
long,  the  disk-  or  cap-shaped  chromatophore  at  the  top  ;  dissepi- 
ments horizontal  or  oblique,  somewhat  curved  upward  ;  terminal 
cells  of  the  same  size  and  form  as  the  others,  but  with  rounded 
top  and  richer  contents ;  sporangia  formed  from  the  superficial 
cells,  little  changed  in  form  or  size,  but  with  tip  more  acute  ; 
zoospores   30-40   in    a  cell,    escaping   by    a  terminal    opening. 
Greenland.  Nothem  Europe. 

At  first  this  plant  is  monostromatic,  resembling  Pringsheimia,, 
and  even  in  this  state  produces  spores.  It  continues  to  increase 
in  thickness,  and  empty  sporangial  cells  may  be  found  quite  a 
distance  below  the  surface  ;  from  the  lower  surface  short  fila- 
ments penetrate  the  host  plant  to  a  greater  or  less  depth. 

2.  U.   FUCICOLA    Rosenvinge,    1893,    p.    926,    fig.   40;   Olt- 
manns,    1894,  p.  211,   PI.  VII,  figs.  11-13.     Frond  pulvinate  or 
hemispherical,  to  75  /*  thick,  somewhat  gelatinous,  composed  of 
oblong  cells  arranged  in  more  or  less  distinctly  radiating  series  ; 
cells  5-7  ft-  diam.,  3-5  diam.  long,  wall  not  sharply  marked  off 
from  the  general   gelatinous  coating  ;  chromatophore  parietal, 
occupying  the  middle  part  of  the  cell ;  all  cells,  except  perhaps 
the  basal  layer,  developing  into  sporangia,  which  swell  to  twice 
the  size  of  the  vegetative  cells,  and  are  pushed  out  from  among 
them  ;  zoospores  6-10  in  a  sporangium.     On  old  plants  of  FUCKS. 
Greenland.  Northern  Eiirope. 

Quite  different  both  in  habit  and  structure  from  U.  conflucns, 
forming  smaller,  not  confluent,  more  gelatinous  fronds  with 
smaller  cells,  and  less  sharply  differentiated  sporangial  layer. 
It  penetrates  the  host  plant,  but  not  to  such  an  extent  as  U. 
confluens, 

3.  U.  LENS  Crouan,  1859,  p.  288,  PI.  XXII,  fig.  E.     Fronds 
orbicular,  1-3  mm.  diam.,  cells  15-20  /*  diam.  in  center  of  frond, 
near  the  margin   10-15X20-30/11;   frond  usually  not  over  three 
layers    thick    in    the    center  of    the  frond.     Fig.    102.     North 
Carolina,  on  stones  and  shells.  Europe. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  287 

Though  this  is  the  original  species  of  the  genus,  the  details 
of  development  and  reproduction  are  not  as  well  known  as  in 
the  two  later  described  species. 

4.  U.  PROSTRATA  Gardner,  1909,  p.  373,  PI.  XIV,  figs,  i 
and  2.  Frond  epiphytic,  the  disk  of  2-3  layers  of  cells  in  the 
middle,  of  one  layer  near  the  margin,  composed  of  radiating 
filaments,  free  at  the  margin,  all  firmly  adherent  to  the  host ; 
cells  each  with  a  band-shaped  chromatophore  and  one  pyrenoid, 
6-7  fj.  diam.,  about  i  diam.  long  near  the  center  of  the  disk,  in- 
creasing to  2j/£  diam.  at  the  tips  of  the  filaments  ;  terminal  cell 
blunt  ;  color  very  dark  green.  On  Iridaea  laminaroidcs  Bory, 
near  San  Francisco,  Cal. 

Forming  obscure,  circular  cushions,  2-3  mm.  diam.  on  the 
host,  usually  in  the  sterile  part  of  the  frond.  The  absence  of 
hairs  and  tapering  cells  would  seem  to  justify  placing  this 
species  in  Ulvella,  but  until  something  is  known  of  the  repro- 
duction, there  must  be  some  uncertainty. 

13.     EPICLADIA  Reinke,  1888,  p.  241. 

Frond  microscopic,  composed  of  filaments  irregularly  and 
densely  branching,  forming  a  coating  on  the  surface  of  Bryozoa  ; 
branching  in  one  plane,  when  well  developed  taking  the  form 
of  a  central  membrane  with  filamentous  margin  ;  chromatophore 
a  parietal  layer  with  one  pyrenoid.  Reproduction  by  zoospores 
(gametes  ?)  formed  many  in  a  cell,  and  escaping  by  a  round 
hole  in  the  wall.  Only  one  species. 

E.  FLUSTRAE  Reinke,  1889,  p.  86;  iSSga,  p.  31,  PI.  XXIV, 
figs.  5-9;  Hazen,  1902,  p.  225,  PI.  XLII,  fig.  2  ;  P.  B.-A.,  No. 
1 60.  Cells  of  the  central  plate  irregularly  polygonal,  usually 
7-12  p.  diam.,  occasionally  larger  ;  of  the  free  filaments  short- 
cylindrical  or  irregular,  5-10  p.  diam.  Fig.  94.  Greenland  to 
N.  Y.  Europe. 

On  the  northern  New  England  coast  this  plant  is  common  in 
spring  and  summer ;  at  New  York,  Hazen  reports  it  in  May, 
but  did  not  find  it  in  summer  and  autumn.  The  Fuci  that 
cover  the  rocks  in  the  literal  zone  are  often  overgrown  with 
Flustra,  Sertularia,  etc.;  these  are  usually  of  a  whitish  or  yel- 
lowish color,  but  when  covered  by  the  Epidadia,  they  are  dark 
green  ;  the  alga  is  thus  easily  detected. 

PRINGSHEIMIA  Reinke,  1888,  p.  241. 

Frond  a  monostromatic  disk  on  the  surface  of  other  algae  ; 
marginal  cells  flat,  interior  cells  wedge-shaped,  with  their 


288          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

length  vertical  to  the  basal  plane  ;  growth  radial  by  division  of 
the  marginal  cells  ;  chromatophore  a  large  disk  with  one  pyre- 
noid.  Asexual  reproduction  by  biciliate  zoospores  with  red- 
brown  stigma,  formed  in  the  central  cells,  few  in  each  cell, 
escaping  through  an  opening  in  the  wall.  Sexual  reproduction 
in  distinct  plants  from  the  asexual,  by  biciliate  gametes  with 
reddish  stigma,  many  in  a  cell.  Only  one  species. 

P.  SCUTATA  Reinke,  18893,  p.  33,  PI.  XXV  ;  P.  B.-A.,  No. 
1524.  Disk  1-2  mm.  diam.  ;  cells  varying  much  in  size  and 
shape;  zoospores  15  /x  diam.,  gametes  4  p..  On  Zostera  and 
various  marine  algae.  Fig.  95.  Greenland  to  Conn.,  Jamaica. 

Europe. 

15.     OCHLOCHAETE  Thwaites  in  Harvey,  1846-1851, 
PI.  CCXXVI. 

Filaments  creeping,  articulate,  branching  ;  all  or  nearly  all 
the  cells  bearing  each  a  very  long,  inarticulate  seta,  base  not 
swollen. 

O.  FEROX  Huber,  1892,  p.  291,  PL  X;  Rosenvinge,  1893,  p. 
931,  fig.  42  ;  P.  B.-A.,  No.  1521.  Filaments  radiating  from  a 
center,  more  or  less  closely  united  to  form  a  round  or  somewhat 
irregular  disk  ;  branching  lateral,  occasionally  a  branch  rising 
above  the  rest  and  forming  locally  a  tissue  two  cells  thick  ;  cells 
rounded  or  angular,  up  to  30 /A  diam.,  chromatophore  parietal 
with  one  pyrenoid  ;  setae  tubular,  continuous  with  the  cells ; 
central  cells  enlarging  to  form  sporangia,  up  to  30  p.  diam., 
which  develop  each  20-30  4-ciliate  zoospores,  developing  at 
once  on  coming  to  rest.  Fig.  92.  On  Cladophora,  Chacto- 
morpha  and  Zostera.  Greenland,  Mass.  Europe. 

O.  hystrix  Thwaites  has  been  reported  from  Washington, 
Setchell  and  Gardner,  1903,  p.  219,  but  there  is  some  doubt  as 
to  the  determination. 

16.  CHAETOPELTIS  Berthold,  1878,  p.  215. 
Frond  a  more  or  less  rounded  disk,  attached  by  the  lower  sur- 
face, gelatinous,  composed  of  rounded  cells,  in  more  or  less  dis- 
tinct radial  series;  cells  uninucleate,  with  one  pyrenoid,  some- 
times with  long,  gelatinous,  hair-like  prolongations  from  the 
cell  wall ;  sexual  reproduction  by  the- union  of  biciliate  gametes  ; 
asexual  reproduction  by  4-ciliate  zoospores  with  red  stigma. 
Fresh  water. 

There  is  some'  question  as  to  the  character  of  the  chromato- 
phore in  this  genus  ;  Berthold,  1878,  in  the  original  diagnosis, 
stating  that  many  small  disk-shaped  chromatophores  were 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  289 

found  in  a  cell;  Huber,  1892,  however,  considers  that  the  ap- 
parent separate  disks  are  thickenings  in  a  single  parietal 
coating. 

C.  americana  (Snow)  nov.  comb.  ;  Ulvella  americana  Snow, 
1899,  p.  309,  PI.  VII.  Disk  1-3  mm.  diam.  ;  marginal  cells 
10-17X5-13  p,  squarish  or  horizontally  elongate;  central  cells 
10-13  /*  diam.,  vertically  elongate,  ultimately  in  several  layers; 
superficial  cells  sometimes  producing  evanescent  gelatinous 
hairs;  zoospores  4-ciliate,  10-15X8-13^,  oval  or  nearly  spheri- 
cal, with  numerous  oil  globules  and  large  brick-red  stigma  ; 
4-8-16  produced  in  a  cell,  from  which  they  escape  together, 
surrounded  by  a  common  gelatinous  envelope  ;  germinating 
immediately  after  coming  to  rest,  and  producing  a  plant  like 
the  parent.  Fig.  96.  Mich. 

The  4-ciliate  zoospores  with  prominent  red  stigma,  issuing 
from  the  mother  cell  in  a  common  envelope,  and  the  gelatinous 
hairs,  all  indicate  Chactopeltis  rather  than  Ulvella  as  the  proper 
genus  for  this  plant.  Moreover,  Ulvella  is  a  strictly  marine 
genus  as  far  as  known,  and  has  a  structure  more  parenchym- 
atous  and  less  gelatinous. 

From  C.  orbicularis  Berthold  and  C.  minor  Mobius  it  would 
seem  to  be  distinguished  by  the  polystromatic  disk.  Some 
peculiar  conditions  noted  by  Miss  Snow,  such  as  germinating 
zoospores  forming  two  or  four  zoospores  of  a  secondary  genera- 
tion ;  also  the  assuming  of  a  sort  of  Palmella-state,  may  be  due 
to  conditions  of  cultivation,  but  at  any  rate  raise  interesting 
questions. 

17.     CHAETOBOLUS  Rosenvinge,  1893,  p.  928. 

Frond  epiphytic,  hemispherical  or  more  rarely  subglobose  ; 
cell  division  in  all  directions  ;  in  the  hemispherical  frond  the 
cells  of  the  basal  margin  radiately  arranged  ;  superficial  cells, 
except  those  of  the  basal  margin,  and  those  covered  by  other 
algae,  produced  into  long  inarticulate  setae,  continuous  with 
the  cells  producing  them  ;  reproduction  by  zoospores  produced 
in  the  superficial  cells  ?  Marine. 

'  Nearly  allied  to  Ochlochaetc,  but  normally  polystromatic,  while 
Ochlochacte  is  normally  monostromatic.     Only  one  species. 

C.  GIBBUS  Rosenvinge,  1893,  p.  928,  fig.  41.  Frond  100-150 
H  diam.,  cells  of  irregular  rounded  form,  up  to  30  /*  diam.,  with 
dense  chromatophore  ;  the  free  superficial  cells  with  very  long, 
slender  setae,  4-5  /u  diam.  at  the  base,  much  more  slender  near 


290          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

the  tip  ;  the  very  narrow  passage  through  the  seta  not  parti- 
tioned off  from  the  cell ;  zoospores  have  not  been  observed,  but 
the  appearance  of  the  fronds  sometimes  indicates  that  they  are 
probably  formed  in  the  superficial,  bristle-bearing  cells.  On 
Chaetomorpha  mclagonium.  Fig.  98.  Greenland. 

This  plant  usually  grows  in  company  with  Lithodcrma  and 
other  epiphytic  algae,  which  often  so  cover  it  that  the  develop- 
ment of  the  setae  is  much  obstructed. 

18.     ARTHROCHAETE  Rosenvinge,  1898,  p.  no. 

Frond  epiphytic  or  endophytic,  incrusting,  orbicular,  pseudo- 
parenchymatous,  sending  towards  the  interior  of  the  host  plant 
filaments  which  branch  and  spread  in  the  medullary  layer  of  the 
latter ;  superficial  vegetative  cells  usually  bearing  each  a  long 
seta,  separated  from  the  cell  by  a  partition,  and  itself  with  one 
or  two  partitions  ;  sporangia  formed  from  superficial  cells,  con- 
stituting a  continuous  layer,  obovoid  or  cylindrical ;  the  zo- 
ospores escaping  by  an  opening  at  the  top.  Marine. 

Only  one  species. 

A.  PENETRANS  Rosenvinge,  1898,  p.  in,  fig.  24.  Frond  to 
\y?  mm.  diam.,  100 /u,  (8  cells)  thick;  sporangia  10-14  /*  diam., 
17-28  /A  long.  In  old  fronds  of  Turncrella  Pennyi.  Fig.  97. 
Greenland. 

Distinguished  from  Ulvella  by  the  presence  of  setae ;  from 
Chaetobohis  by  the  articulate  character  of  the  setae,  as  well  as 
by  the  filaments  penetrating  the  host  plant. 

19.  GONGROSIRA  Kiitzing,  1843,  P-  2^1- 
Fronds  of  densely  packed,  articulate,  simple  or  sparingly 
branched  filaments,  each  attached  by  a  disk-shaped  expansion  ; 
cells  about  as  long  as  broad  or  somewhat  longer  ;  chromato- 
phore  parietal,  occupying  nearly  all  the  cell  wall,  with  one  pyre- 
noid  ;  asexual  reproduction  by  biciliate  zoospores,  also  by 
akinetes. 

A  genus  long  considered  doubtful,  and  from  which  most  of 
the  species  have  been  removed  ;  but  probably  to  be  maintained 
for  the  few  remaining  species. 

G.  DEBARYANA  Rabenhorst,  Algen,  No.  223;  Wille,  1887, 
p.  484,  PI.  XVIII,  figs.  106-114;  PL  XIX,  figs.  115-135;  P. 
B.-A.,  No.  1187.  Filaments  ascending,  bright  green,  dichoto- 
mous,  forming  an  irregular  expanded  stratum  ;  cells  of  varying 
shape,  15-30,  rarely  40  /A  diam.,  1-2  diam.  long;  membrane  at 
first  thin,  becoming  thick  and  lamellate  ;  terminal  cell  swollen, 


THE  GREEN  ALGAE  OF  NORTH  AMERICA          291 

up  to  50  p.  diam.,  developing  into  an  orange  colored  akinete,  or 
else  developing  into  a  sporangium  producing  16  or  more  biciliate 
zoospores.  On  submerged  wood,  stones,  and  shells  ;  fresh  water. 
Fig.  91.  Cal.  Europe. 

20.  CHLOROTYLIUM  Kiitzing,  1843,  p.  285. 
Frond  consisting  of  erect,  branching,  articulate  filaments, 
forming  bright  green,  firm,  pulvinate  coatings,  sometimes  in- 
crusted  with  lime ;  cells  with  band-shaped  chromatophore, 
(with  pyrenoid  ?)  ;  asexual  reproduction  by  biciliate  zoospores, 
formed  in  large  numbers  in  the  cells  ;  also  by  4-ciliate  zoospores 
formed  4-16  each  in  small  cells,  resulting  from  division  of  the 
vegetative  cells  ;  also  by  akinetes.  Fresh  water. 

C.  CATARACTARUM  Kiitzing,  1843,  p.  285,  PL  XVII;  Phyc. 
Univ.,  No.  290.  At  first  in  minute  tufts,  up  to  4  mm.  diam., 
soon  confluent  to  a  continuous  layer  ;  filaments  parallel,  densely 
packed,  6-12  /j.  diam.,  of  two  kinds,  one  kind  bright  green,  cells 
1^-2  diam.  long,  the  other  lighter,  nearly  hyaline,  cells  2-6 
diam.  long  ;  akinetes  orange  or  vermilion,  formed  only  from  the 
shorter  cells,  9-15  p-  diam.,  globose  or  oblong- ellipsoid.  Fig.  86. 
N.  Y.,  Ky.  Europe. 

21.     PILINIA  Kiitzing,  1843,  p.  273. 

Basal  layer  of  abundantly  branched  filaments,  from  which 
arise  erect  filaments,  simple  or  branched,  sometimes  terminating 
in  articulate  hairs ;  chrdmatophore  covering  the  cell  wall  ; 
sporangia  roundish,  ovoid  or  clavate,  terminal  or  lateral  on 
erect  filaments  or  sessile  on  the  basal  layer,  the  contents  form- 
ing numerous  biciliate  zoospores,  which  escape  through  an 
opening  at  the  summit ;  development  unknown. 

KEY  TO  THE  SPECIES  OF  PILINIA. 

i.     Filaments  often  ending  in  hairs.  7.     P.  maritima. 

i.     Hairs  not  present.  2. 

2.     Endophytic.  3.     P.  endophytica. 

2.     Not  endophytic.  •  3. 

3.     Erect  filaments  short,  densely  packed.  4. 

3.     Erect  filaments  longer,  yellowish.  5. 

4.     Dark  green  ;  filaments  8-12  /u.  diam.;  on  live  shells. 

i.     P.  Lunatiae. 
4.     Yellowish  green  ;  filaments  2-5  M  diam.;  on  pebbles. 

2.     P.  minor. 
5.     Forming  a  rather  firm,  spongy  coating  on  woodwork. 

5.     P.  rimosa. 
5.     Forming  a  thin,  soft  coating.  6. 


292  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

6.     On  shells,  pebbles,  etc.;  sporangia  on  erect  filaments. 

4.     P.  Reinschii. 

6.     On  woodwork  ;    sporangia  on  basal  layer,  rarely  lateral  on  erect 
filaments.  6.     P.  Morsei. 

1.  P.  LUNATIAE  Collins,    1908,  p.    123,   PI.  LXXVII,  figs. 
1-3;    Acroblaste  Reinschii  P.  B.-A.,   No.    162.     Basal  filaments 
soon  becoming  united  into  a  subparenchymatous  layer,  cells  of 
varying  shape  and  size,  roundish  or  angular,  up  to  15  /*  diam.; 
erect  filaments  8-12  p.  diam.,  increasing  in  size  upward,  usually 
5-6  cells  in  length,  quite  rarely  up  to  10  cells,  densely  branched 
and  very  compact,  cells  varying  in  size  and  shape  in  the  same 
filament ;  terminal  cell  becoming  the  sporangium,  differing  but 
little  from  any  other  cell  of  the  filament ;  color  deep  green.     On 
live  shells  of  Lunatia  heros  Adams.     Mass. 

Very  common  on  Lunatia  shells  at  Revere  Beach,  Mass.,  but 
not  reported  elsewhere.  It  forms  a  very  deep  rich  green  coating 
at  the  flat  spiral  of  the  shell,  but  on  living  shells  only.  The 
substance  is  very  compact,  the  filamentous  character  being  made 
out  with  difficulty.  The  spores  are  produced  in  the  terminal 
cells  of  the  upright  filaments,  slightly  enlarged,  but  not  other- 
wise changed.  It  is  a  plant  of  spring  and  early  summer  chiefly. 

2.  P.    MINOR    Hansgirg   in  Foslie,    1890,    p.    146,    PI.    II, 
figs.    17-22.      Stratum   thin-coriaceous  or  almost   crustaceous, 
yellow-green,  more  or  less  extended  ;  basal  layer  dense,  indi- 
vidual  filaments  indistinguishable ;    erect   filaments   irregular, 
vertical  or  inclined,  as  small  as  2  /u.  diam.  at  the  base,  increas- 
ing in  size  upward  to  as  much  as  7  yn  at  the  summit ;  not  much 
branched.     Sporangia  terminal,  pyriform  but  rather  irregular, 
20-24 X  10- 12 //..     On  pebbles  by  the  seashore.      Mass. 

Northern  Europe. 

The  distinction  between  the  basal  and  the  erect  filaments  is 
less  than  in  P.  Limatiae,  but  the  sporangia  are  more  clearly  dif- 
ferentiated. In  the  onjy  recorded  American  locality,  it  grew  on 
pebbles  between  high  and  low  tide  marks,  and  when  the  tide 
was  out  was  wet  with  cold  water  from  a  spring. 

3.  P.   ENDOPHYTICA  Collins,    igoSc,   p.    156.     Frond  of  no 
definite  form,  consisting  of  usually  short,  simple  or  branched 
filaments,  creeping  among  the  filaments  of  the  host ;  cells  vari- 
able  in   form   and   size,   cylindrical,    clavate,    subspherical   or 
irregular,   7-22  p.  diam.,    1-5  diam.  long;  chromatophore   light 
green,  sometimes  filling  the  cell,  more  commonly  cup-shaped, 
at  the  upper  end  of  the  cell.     Sporangia  terminal,  spherical  or 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  293 

ovoid,  up  to  to  30  fj.  diam.,  containing  numerous  spores.     In 
fronds  of  Ralfsia  Borneti  Kuckuck.     Me.  to  Conn. 

4.  P.  REINSCHII  (Wille)  Collins,  1908,  p.  125  ;  Acroblaste  sp. 
Reinsch,    1879,    p.    365,  PI.    III. A.      Basal    layer  of   monosi- 
phonous  filaments,  with  rounded  cells  about  as  long  as  broad  ; 
vertical  filaments  about  >^  mm.  high,  5-8  //.  diam.,  cells  about 
twice  as  long  as  broad,  cylindrical  or  slightly  constricted  at  the 
nodes  ;  sporangia  ovoid,  16-20X20-25  p. ;  terminal  or  apparently 
lateral  on  the  erect  filaments.     On  shells  and  pebbles.     Mass. 

In  this  species  the  basal  layer  shows  the  filamentous  character 
throughout,  even  when  the  filaments  are  laterally  united  ;  often 
they  remain  practically  free.  The  color  is  a  yellowish,  some- 
what olivaceous  green  ;  it  has  some  resemblance  to  a  small 
species  of  Edocarpus.  It  is  often  mixed  with  Microchaete  grisea 
Thuret,  Calothrix  species,  and  other  small  algae. 

5.  P.  RIMOSA  Kiitzing,  1843,  p.  273  ;   1854,  p.  20, 'PI.  XC.  ; 
P.  B.-A.,  No.  971.     Forming  a  dense,  yellowish  green  stratum  ; 
basal  layer  of  somewhat  irregular  cells,  more  or  less  torulose  ; 
erect  filaments  reaching  a  height  of  2  mm.,  simple  or  branched, 
cylindrical  or  torulose,  cells  7-10  /u,  diam.,  length  of  cell,   1-2 
diam.  ;  reproduction  unknown.     On  woodwork  near  high  water 
mark.     Me.  Europe. 

Forms  a  very  compact  coating,  that  can  be  removed  in  pieces 
of  considerable  size  ;  Calothrix  pulvinata  grew  with  it  at  the 
Maine  locality,  nearer  low  water  mark  ;  the  stratum  was  con- 
tinuous, Calothrix  below,  Pilinia  above,  the  two  mixed  for  a 
space  in  the  middle. 

6.  P.  MORSEI  Collins,   1908,  p.  126,  PL  LXXVII,  figs.  4-6. 
Basal  filaments  irregularly  contorted,  more  or  less  united ;  cells 
rounded,  8-15  /*  diam.,  often  divided  longitudinally  and  forming 
a  subparenchymatous  membrane  of  two  or  more  layers ;  erect 
filaments  up  to  2  mm.  high,  7-11  M  diam.,  cells  1-2  diam.  long, 
cylindrical  or  slightly  moniliform  ;  sporangia  ovoid  or  pyriform, 
on  the  basal  layer,  sessile  or  on  a  few-celled  pedicel.     Fig.  90. 
On  woodwork,  N.  J. 

Showing  more  differentiation  than  the  preceding  species, 
assimilative  and  fertile  growths  being  both  distinct  from  the 
basal  layer. 

7.  P.  MARITIMA  (Kjellm.)  Rosenvinge,  1893,  p.  933,  fig.  43  ; 
Chaetophora  maritima  Kjellman,    1877,  p.  51,   PI.  IV,  figs.  15 
and  16.      Frond  subspherical,  1-3  mm.  diam.,  basal  layer  not 


294  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

strongly  developed  ;  erect  filaments  6-10  p.  diam. ;  cells  about 
as  long  as  broad,  terminating  in  an  inarticulate  hair,  or  in  an 
ovate-ellipsoid  cell ;  sporangia  terminal,  clavate,  11-12X16-21  p.. 
Greenland. 

This  species  forms  a  continuous  layer,  in  company  with  Calo- 
thrix  ;  the  subspherical  gelatinous  thalli  distinguish  it  from  the 
other  species  of  the  genus.  Under  this  should  be  included,  ac- 
cording to  Rosenvinge,  C.  pcllicnla  Kjellman,  1883,  p.  286,  PL 
XXXI,  figs.  4-7,  which  forms  a  thin  slimy  membrane  on  wood  ; 
Rosenvinge  was  unable  to  find  the  intercalary  sporangia  to 
which  Kjellman  refers,  and  which,  if  confirmed,  would  require 
the  removal  of  the  plant  to  another  genus. 

22.     MICROTHAMNION  Nageli  in  Kiitzing,  1849,  p.  352. 

Frond  very  minute,  consisting  of  a  branching,  monosiphonous 
filament,  attached  by  a  bulbous  base  ;  stem  and  branches  of 
about  the  same  size  ;  first  partition  in  branch  some  distance 
above  base  ;  terminal  cell  blunt ;  cells  cylindrical,  with  thin 
wall ;  chromatophore  a  thin  sheet,  more  or  less  completely 
covering  the  cell  wall,  without  pyrenoid.  Asexual  reproduc- 
tion by  ovoid,  biciliate  zoospores  without  stigma,  germinating 
immediately. 

A  genus  of  very  minute  plants,  the  frond  not  reaching  the 
height  of  i  mm.  ;  in  appearance  resembling  a  small  Trente- 
pohlia,  but  differing  in  that  the  spores  are  produced  in  any  cell 
of  the  filament,  practically  unchanged  ;  not  in  more  or  less 
specialized  sporangia. 

KEY  TO  THE  SPECIES  OF   MICROTHAMNION. 
i.     Ramification  dense  ;  main  stem  aiid  branches  indistinguishable. 

i.     M.  Kutzingianuin. 
i.     Ramification  open  ;  main  stern  distinguishable  throughout. 

2.     M.  strictissintinn. 

i.  M.  KUETZINGIANUM  Nageli  in  Kiitzing,  1849,  P-  352  >" 
Hazen,  1902,  p.  191,  PL  XXVI,  fig.  i  ;  PL  XXVII,  figs.  2-4; 
P.  B.-A.,  No.  568.  Up  to  200  /A  tall,  very  densely  and  irregu- 
larly branched,  main  stem  and  branches  indistinguishable ; 
ramuli  one-  to  several-celled,  patent  or  curved  ;  cells  cylindrical 
or  slightly  clavate,  3-4  p.  diam.  in  all  parts  of  the  frond,  usually 
2-4  diam.  long,  occasionally  considerably  longer  ;  chromato- 
phore bright  green,  usually  covering  the  entire  cell  wall.  Fig. 
83.  Mass,  to  N.  Y.  Europe,  New  Zealand. 

Forming  a  thin  coating  on  sticks,  woodwork,  etc.,  in  streams  ; 
also  in  greenhouses. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  295 

2.  M.  STRICTISSIMUM  Rabenhorst,  Algen,  No.  829;  Ha/en, 
1902,  p.  191,  PI.  XXYI,  figs.  2-5;  P.  B.-A.,  No.  1425.  Up  to 
600  /u.  tall,  erect,  branching  mostly  alternate,  the  main  stems  dis- 
tinguishable throughout ;  branches  erect  or  ascending ;  cells 
cylindrical,  2.5-4  p.  cliam.,  about  the  same  size  all  through  the 
frond,  3-12  diain.  long,  or  even  more;  chromatophore  thin,  pale 
green,  often  only  partially  covering  the  wall.  Conn.,  N.  Y. 

l^urope,  So.  America. 

In  similar  stations  to  the  preceding  species ;  distinguished  by 
the  greater  size,  longer  articulations,  and  different  ramification. 

Yar.  MACROCYSTIS  Schmidle,  1899,  p.  169, Tl.  VII,  figs.  1-3; 
Hazen,  1902,  p.  192,  PI.  XXVII,  fig.  i.  Taller,  branching 
more  open ;  branches  more  slender  than  main  stem,  somewhat 
tapering ;  chromatophore  pale  and  narrow ;  tips  of  branches 
colorless.  Mass.,  N.  Y.  Europe. 

Found  growing  on  dead  leaves  in  a  rain  water  ditch. 
23.     CHAETOPHORA  Schrank,  1813,  p.  124. 

Filaments  arising  from  a  palmelloid  base,  and  united  by  a  firm 
gelatinous  substance  into  thalli  of  definite  form  ;  filaments  re- 
peatedly branched,  of  about  the  same  diameter  throughout, 
ramuli  often  in  fascicles,  frequently  terminating  in  long  setae. 
Chromatophore  a  parietal  band  with  one  or  more  pyrenoids. 
Asexual  reproduction  by  biciliate  zoospores,  formed  in  the  cells 
of  the  ramuli ;  akinetes  from  any  cell. 

The  filaments  are  much  like  those  of  Stigeoclonium ,  but  the 
branching  has  more  of  a  dichotomous  appearance  ;  the  whole  is 
imbedded  in  a  gelatinous  mass  of  definite  form,  spherical,  tuber- 
cular, or  elongate  and  branching.  The  plants  are  attached  to 
sticks,  stones,  etc.,  and  are  common  in  clear  running  water  in 
spring  ;  less  common  in  quiet  water. 

KEY  TO  THE  SPECIES  OF  CHAETOPHORA. 

r.     Thalli  elongate,  lobed  and  branching.  4.     C.  incrassata. 

i.     Thalli  globose  or  tuberculose.  2. 

2.     Branching  loose  and  spreading.  i.     C.  elegans. 

2.     Branching  erect.  3. 

3.     Branches  fascicled  at  the  summit.  2.     C.  pisifor^is. 

3.     Branches  not  fascicled  at  the  summit.  3.     C.  attenuata. 

i.  C.  ELEGANS  (Roth)  Agardh,  1812,  p.  42;  Wolle,  1887, 
p.  116,  PL  CIII,  fig.  4-10 ;  Hazen,  1902,  p.  211,  PI.  XXXVII; 
P.  B.-A.,  No.  1026.  Thalli  globose  or  oftener  tuberculose,  up 
to  i  cm.  diam,  light  green,  rather  soft ;  filaments  radiating  from 
the  center,  di-trichotomously  branched  and  fasciculate  above ; 


296          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

branches  loose  and  spreading,  except  sometimes  at  the  tips ; 
ramuli  short-pointed  or  setiferous  ;  cells  in  main  filaments  6-u, 
usually  8 /*  diam.,  3-10  diam.  long;  in  ramuli  5-7  /*  diam.,  1-4 
diam.  long.  Fig.  85.  Mass,  to  N.  J.,  Jamaica,  Washington. 

Europe. 

Ranging  in  size  from  hardly  visible  spheres  to  tuberculose  and 
confluent  forms,  over  i  cm.  diam.  ;  mostly  in  spring,  but  occa- 
sionally at  any  time  except  when* the  brooks  are  frozen.  In 
general  character  much  like  the  two  following  species,  but 
generally  of  lighter  color,  softer  texture,  and  less  regularly 
spherical  shape. 

2.  C.  PISIFORMIS  (Roth)  Agardh,  1812,  p.  43  ;   Harvey,  1858, 
p.  70;   Wolle,   1887,   p.  116,   PL  CIII,   figs.  1-3,  12-15;   Hazen, 
1902,  p.  212,  PL  XXXVIII,  fig.  i.     Thalli  globose  or  tubercu- 
lose, 2-5  mm.  diam.,  rather  dark  green,  firm,  seldom  confluent ; 
filaments  radiating  from  the  center,  dichotomously,  rarely  tri- 
chotomously    branched,    branches  erect    or   appressed,    ramuli 
slender,   acute,   sometimes  setiferous ;    cells  in  main  filaments 
usually  6-7  p.  diam.,  sometimes  slightly  more  or  less,  3-6  diam. 
long;  in  ramuli  4-6  p  diam.,   1-3   diam.   long.     Me.  to  N.  J., 
Washington.  Europe. 

The  habit  characters  by  which  this  differs  from  C.  elegans  are 
given  under  the  latter  species  ;  microscopically,  C.  pisiformis  has 
more  slender  filaments  and  more  erect  branching.  The  charac- 
ter of  presence  or  absence  of  setae,  formerly  supposed  to  be  of 
specific  importance,  is  now  known  to  be  of  no  value,  varying 
with  age  and  circumstances.  This  species  is  especially  a  plant 
of  running  water. 

3.  C.  ATTENUATA  Hazen,   1902,  p.   213,   PL  XXXIX;   P. 
B.-A.,  No.  1520.     Thalli  globose  or  nearly  so,   not  confluent, 
2-5  mm.   diam.,   bright   green,   dense  and  firm  ;    filaments  di- 
trichotomously  branched,   very  erect    and   nearly  parallel,   not 
fasciculate  ;  ramuli  acute  or  setiferous  ;  cells  of  main  filaments 
5-5.5  p.  diam.,  5-10  diam.  long ;  of  the  ramuli  about  4  ^,  rather 
longer  in  proportion  ;   branch-bearing  cells  often  broadened  and 
forked  at  the  top ;  descending  rhizoids   abundant  in  the  lower 
part  of  the  frond.     Mass.,  Conn.,  N.  J. 

In  habit  quite  like  C.  ptsiformu,  but  distinguished  by  more 
slender  filaments,  very  regular  branching,  ramuli  long  and 
rather  distant,  rhizoids  abundant.  A  plant  of  quiet  water,  and 
of  summer  rather  than  of  spring. 

4.  C.    INCRASSATA    (Huds.)    Hazen,     1902,    p.    214,     PL 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  297 

XXXVIII,  figs.  2  and  3  ;  P.  B.A.,  1330  ;  C.  endivaefolia  Harvey, 
1858,  p.  69  ;  Wolle,  1887,  p.  117,  PI.  CIV  ;  C.  cornu-da-mac  P. 
B.-A.,  No.  68.  Thalli  irregularly  extended,  lobed,  laciniate,  or 
branched,  main  filaments  elongate,  closely  packed  in  skeins  or 
strands,  with  alternate  or  secund  branches  bearing  densely 
fascicled,  usually  setiferous  ramuli ;  cells  of  main  filaments 
8-16  /A  diam.,  2-6  diam.  long,  cylindrical  or  inflated;  ramuli 
often  curved,  often  torulose,  6-n  /u.  diam.,  cells  1-2  diam.  long. 
Generally  distributed.  Europe,  So.  America. 

Thoroughly  distinct  from  the  three  preceding  globular 
species,  but  varying  so  much  in  form  and  ramification  that  it 
has  received  many  specific  and  varietal  names,  but  no  clear  lines 
can  be  drawn.  Much  of  the  variation  appears  to  be  due  to  the 
rapidity  of  the  water  in  which  it  grows  ;  between  the  forms  with 
somewhat  flattened  and  lobed  thallus,  2-3  cm.  long,  and  the 
slender,  much  branched,  filamentous  forms,  several  dm.  long, 
every  gradation  can  be  found. 

24.  STIGEOCLONIUM  Kiitzing,  1843,  P-  253- 
Frond  mucilaginous,  composed  of  a  branching  filament,  with- 
out much  distinction  in  character  between  main  filaments  and 
branches ;  terminal  cells  pointed  or  prolonged  into  a  seta ; 
chromatophore  a  parietal  band,  filling  the  smaller  cells,  zonate 
in  the  larger.  Asexual  reproduction  by  4-ciliate  zoospores  with 
a  red  stigma ;  also  by  akinetes  which  produce  2-ciliate  zo- 
ospores, by  aplanospores,  and  also  by  a  Palmella  stage.  Sexual 
reproduction  by  conjugation  of  2-ciliate  gametes  with  a  red 
stigma. 

A  rather  large  genus  of  fresh  water  algae,  very  well  limited 
but  whose  species  show  few  sharp  dividing  lines. 

KEY  TO  THE  SPECIES  OF  STIGEOCI.ONIUM. 

i.     Opposite  branching  predominant.  2. 

I.     Alternate  branching  predominant.  8. 

2.     Filaments  10  /tx  diam.  or  less.  6.     5".  tenue. 

2.     Filaments  11-30 /u  diam.  3. 

3.     Lower  cells  much  inflated.  5.     S.  ventricosum. 

3.     Lower  cells  slightly  or  not  at  all  inflated.  4. 

4.     Lower  cells  not  over  2  diam.  long.  5. 

4.     Lower  cells  2-8  diam.  long.  6. 

5.     Lower  cells  seldom  as  long  as  broad  ;  ramuli  tapering,  thorn-like. 

4.     S.  subuligerum* 
5.     Lower  cells  usually  longer  than  broad  ;  ramuli  short- pointed. 

i.    S.  lubricum. 


298  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

6.     Lower  cells  2-5  diam.  long.  i.     S.  lubricum  var.  varians. 

6.     Lower  cells  3-8  diam.  long.  7- 

7.     Ramuli  pointed.  2.     5.  amoenum. 

7.     Ramuli  setiferous.  3.     S.  flagelliferum. 

8.     Filaments  short,  tufted.  9- 

8.     Filaments  more  elongate.  12. 

9.     Of  thermal  waters.  7-     •$".  thermale. 

9.     Of  ordinary  temperatures.  10. 

10.     Tips  obtuse  or  short-pointed.  8.     S.  nanum. 

10.     Tips  attenuate  or  setiferous.  n. 

ii.     Ramuli  scattered.  13- 

ii.     Ramuli  densely  fasciculate.  10.     S.  glomeratum. 

12.     Filaments  5-7  M  diam.  ii.     S.  attenuatum, 

12.     Filaments  8-1 1 /*  diam.  12.     5.  stagnatile. 

12.     Filaments  12-18  M  diam.  13.     S.  subsecundum. 

13.     Filaments  7-9  M  diam.  9.     S.  aestivale. 

13.     Filaments  4-6  M  diam.  14-     •$".  minus. 

i.  S.  LUBRICUM  (Dillw.)  Kiitzing,  1845,  p.  198;  P.  B.-A., 
No.  866  ;  5".  tenue  var.  lubricum  Wolle,  1887,  p.  in  ;  Myxonema 
lubricum  Hazen,  1902,  p.  195,  PI.  XXVIII,  figs,  i  and  2. 
Tufts  up  to  30  cm.  long,  dark  green,  filaments  much  branched, 
the  branching  principally  of  the  opposite  type,  but  often  several 
pairs,  single  branches  or  whorls  arising  from  adjacent  cells, 
these  cells  being  subglobose  and  smaller  than  other  cells  in  the 
same  filament ;  ramuli  abundant,  opposite,  scattered,  or  near 
the  ends  of  the  branches  in  more  or  less  dense  fascicles ;  smaller 
than  the  branches  from  which  they  arise,  but  only  slightly  if  at 
all  tapering ;  usually  ending  in  a  short  point,  but  sometimes 
setiferous;  lower  cells  somewhat  swollen,  14-17  p-  diam.,  ^3-2 
diam.  long,  rarely  more,  with  broad  zonate  chromatophore ; 
ramuli  6-7  /A  diam.,  cells  about  as  long  as  broad.  Fig.  84. 
Ontario,  Mass,  to  N.  J.,  Alaska.  Europe. 

The  largest,  and  at  least  in  the  eastern  states,  the  most  com- 
mon of  our  species ;  all  the  species  with  prevailingly  opposite 
branching  are  grouped  round  this,  resembling  it  in  most  charac- 
ters, but  with  special  developments  on  one  or  more  lines.  Like 
most  of  the  species  of  Stigeoclonium  it  is  a  spring  plant,  inhabit- 
ing clear  running  water. 

Var.  varians  (Hazen)  nov.  comb.  ;  Myxonema  lubricum  var. 
varians  Hazen,  1902,  p.  198,  PI.  XXVIII,  figs.  3  and  4;  PI. 
XXXIII,  figs.  4  and  5  ;  P.  B.-A.,  No.  1075.  Tufts  short,  not 
exceeding  2  cm.  ;  filaments  seldom  over  12  p.  diam.,  cells  2-5 
diam.  long,  with  thin  wall ;  ramuli  longer-pointed.  Mass,  to 
New  Jersey. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  299 

Appearing  like  a  small  and  delicate  state  of  S.  lubricum,  but 
considered  by  Hazen,  who  collected  it  in  many  localities,  as  a 
well  defined  variet3r. 

2.  S.  AMOENUM  Kiitzing,  1845,  p.  198;  Wolle,  1887,  p.  113, 
PI.  XCVIII,  fig.  4;   P.  B.-A.,   No.    1073;  Myxonema  amoenum 

'  Hazen,  1902,  p.  199,  PI.  XXIX.  I/ight  green,  tufted,  up  to  10 
cm.  long  ;  filaments  much  branched,  after  the  type  of  51.  hibri- 
cuni  ;  the  ramuli  tapering  and  pointed  but  rarely  setiferous  ; 
cells  in  main  branches  cylindrical  or  slightly  inflated,  11-16  /u. 
diam.,  3-8  diam.  long,  occasionally  as  much  as  15  diam.  ; 
shorter  above,  in  the  upper  branches  about  as  long  as  broad ; 
ramuli  6-8 /x  diam.  at  base.  Mass.,  R.  I.,  Conn.  Europe. 

3.  S.  FLAGELLIFERUM  Kiitzing,    1845,    p.   198;    1853,  PI.  X, 

fig.  i  ;  Wolle,  1887,  p.  112,  PI.  XCVII,  fig.  i  ;  P.  B.-A.,  No. 
408  ;  Myxonema  flagettiferum  Hazen,  1902,  p.  199.  Tufts  up  to 
2  cm.  long,  bright  green;  branches  mostly  in  pairs,  2-4  pairs  on 
successive  globose  cells  ;  ramuli  flagelliform,  tapering  into  long 
setae;  lower  cells  14-18  ^  diam.,  4-8  diam.  long,  cylindrical  or 
slightly  inflated  ;  ramuli  9-10  n  diam.  at  base.  Mass.,  Conn. 

Europe. 

This  and  the  preceding  species  have  much  in  common,  but 
5".  flagettiferum  is  larger,  with  more  elongate  and  tapering 
branches,  and  more  abundant  and  better  developed  setae. 

4.  S.  SUBULIGERUM  Kiitziiig,  1849,  p.  354;  Myxonema  subu- 
ligerum  Hazen,    1902,  p.    200,  PI.  XXX.     Tufted,    less  than  i 
cm.  long  ;   much   branched    after  the  type   of  6*.  lubricum,  but 
branches  spreading,  ramuli  divaricate,  tapering  from  the  rather 
thick  base  to  an  acute  point,  or  occasionally  into  a  short  seta  ; 
cells  cylindrical,  about  as  long  as  broad,  quite  covered  by  the 
dense  chromatophore ;    main   branches    12-16  n  diam.;  ramuli 
6-9  fj.  diam.  at  base.     N.  Y.,  N.  J.,  Cal.  Europe. 

Distinguished  by  the  nearly  uniformly  opposite,  divaricate 
branching,  thorn-like  ramuli,  and  dense  chromatophores. 

5.  S.  ventricosum  (Hazen)  nov.  comb.;  Myxonema  vcntri- 
cosum   Hazen,    1902,  p.  201,   PI.  XXXI.     Tufted,  up  to  i  cm. 
long ;   main   branches  as  in  6".   lubricum ;    ramuli  alternate  or 
opposite,   short,  tapering  to  the  rounded  tip  or  into  a   short, 
rather  obtuse  seta;  lower  cells  much  inflated,  14-16  //.  diam.  at 
the  ends,  27-30  /u  at  the  middle,  length  45-110^;  ramuli  6-8 /A 
diam.  at  the  base  ;  chromatophore  a  narrow  zone  in  the  large, 
inflated  cells,  occupying  the  greater  part  of  the  smaller  cells. 
N.  J. 

The  strongly  inflated  cells,  with  comparatively  narrow  zonate 


300  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

chromatophores,  remind  one  of  a  Draparnaldia,    and   seem  to 
characterize  the  species  sufficiently. 

6.  S.  TENUE  (Ag.)  Kiitzing,   1843,  p.  253;  Wolle,  1887,  p. 
no,  PL  XCVI,  fig.  ii  ;  Wittr.  and  Nordst.,  Alg.  Exsicc.,  No. 
1429;    Myxonema    tenuc   Hazen,    1902,    p.    202,    PL    XXXII. 
Tufts  up  to  i  cm.  high,  bright  green  ;  filaments  slender,  7-10  p- 
diam.  below,  5-6  p.  in  the  ramuli ;  cells  cylindrical  or  slightly 
swollen,    1-3  diam.   long;   in  ramuli  about  as  long  as  broad; 
main  branches  solitary  or  opposite,  not  many  pairs  together; 
ramuli  numerous,  scattered  or  opposite,  short,  erect,  tapering  to 
an  acute  point  or  a  very  slender  seta.     Mass.,  Conn.,  Vermont, 
N.  Y.,  Cal.  Europe. 

A  slender,  loosely  branched  species,  forming  a  transition  from 
the  opposite-branching  6".  lubricum  group,  to  the  less  luxuriant, 
alternately  branched  species. 

7.  S.  THERMALE  A.  Braun  in  Kiitzing,  1849,  p.  353;    1853, 
PL  II,  fig.  4  ;   Wolle,  1887,  p.  in,  PL  XCVI,  fig.  i  ;  Myxonema 
thermale  Hazen,  1902,  p.  203.     Filaments  with  somewhat  creep- 
ing base,  freely  branching,  ramuli  distant,  alternate  or  opposite, 
erect  or  patent,  tapering  to  a  point ;  cells  7.5-12  p.  diam.  below, 
1-2  diam.  long ;  in  ramuli  3-5  diam.  long. 

A  plant  of  warm  springs  and  hot  water  escapes  from  mills,  etc.' 

8.  S.  NANUM  (Dillw.)  Kiitzing,   1849,  p.  354;   Wolle,  1887, 
p.    112,    PL    XCVI,  fig.    10 ;    P.   B.-A.,    No.    867;    Myxonema 
nanum  Hazen,  1902,  p.  204.     Two  to  three  mm.  high;   branch- 
ing alternate,  ramuli  tapering,  obtuse  or  short-pointed  ;    cells 
6-8  /A  diam.,  1-2  diam.  long.     Neb.,  So.  Dakota,  Cal.       Europe. 

A  not  very  strongly  characterized  species  ;  perhaps  a  state  of 
some  other,  but  at  present  there  is  no  evidence  to  connect  it 
with  any  other  form.  As  P.  B.-A.,  No.  1375,  there  was  dis- 
tributed, as  forma  subsimplex  Collins,  a  form  from  California, 
with  filaments  even  shorter  than  in  the  type  and  hardly  at  all 
branched. 

9.  S.   aestivale   (Hazen)    nov.  comb.;    Myxonema   aestivale 
Hazen,   1902,   p.   205,    PL   XXXIII,  figs.   1-3;    P.  B.-A.,   No. 
1074.     Light  green,  forming  dense  tufts  up  to  i  cm.  high  ;  base 
palmelloid ;    branching  alternate  or  dichotomous,  erect ;    main 
filaments  7-9  p.  diam.,  rarely  more;  cells  2-6  diam.  long  below, 
about  as  long  as  broad  above,  thin-walled,  somewhat  swollen ; 
ramuli  few,  scattered  or  somewhat  approximate  near  the  sum- 
mit, frequently  attenuate  into  fine  setae.     Growing  in  dense  tufts 
along  the  edges  of  troughs  and  fountains.     Vermont,  Mass., 
N.  Y.,  Conn.  . 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  301 

10.  S.  glomeratum  (Hazen)  nov.  comb.;  Myxonema glomer- 
atmn   Hazen,    1902,   p.  205,   PI.  XXXIV.     Tufts  up  to   i   cm. 
long,   with    palmelloid   base ;    branches   few   below,    alternate ; 
above  more  frequent,  usually  alternate,  rarely  opposite,  more  or 
less  densely  fascicled  near  the  summit,  the  ramuli  tapering  to 
an  acute  tip  or  a  long  seta  ;  cells  of  main  filaments  cylindrical 
or  slightly  swollen,  11-14  M  diam.,  2-7  diam.  long,  with  broad, 
xonate  chromatophore  ;  cells  of  ramuli   6-8  p  diam.,  1-2  diam. 
long,    with   dense    chromatophore.     In    pools    and    fountains. 
Conn.,  N.  V. 

11.  S.  attenuatum  (Hazen)   nov.  comb.;    Myxonema  aiten- 
iiatnm  Hazen,   1902,    p.  206,    Pi.  XXXV;   P.  B.-A.,  No.  1328. 
Tufted  or  forming  dark  green  lubricous  skeins,  up  to  nearly 
half  a  meter  long  ;  dichotomously  divided  near  the  base  into 
man)7  filaments,   sparingly  branched  above ;  ramuli  short,  spi- 
nescent  or  flagelliform,  solitary  or  2  or  3  arising  from  the  same 
point,  less  often  opposite,  tapering  to  an  acute  tip  or  a  very 
slender  seta;    cells  cylindrical,   5-7   ^   diam.,   2-5  diam.  long; 
chromatophore  thin  and  somewhat  broken.     Vermont,   Mass., 
Conn. 

Growing  in  watering  troughs,  where  it  has  the  habit  of  an 
Ulothrix  rather  than  of  a  Stigeocloniiun.  In  the  two  localities 
where  it  has  been  studied,  it  was  found  from  Feb.  to  Nov. 

12.  S.  stagnatile  (Hazen)  nov.  comb.;  Myxonema  stagnatile 
Hazen,  1902,  p.  207,  PI.  XXXVI,  figs,  i  and  2.     P.  B.-A.,  No. 
1329.     Forming  floccose,  floating  masses;    filaments  elongate, 
bearing  at    long  intervals   solitary   or   opposite  ramuli ;  short, 
thorn-like,   often  curved,  tapering  to  a  sharp  point  or   a  long 
seta;   cells  8-n   p.  diam.,  1-3  diam.   long,  occasionally  longer  ; 
ramuli  7-9  /*  diam.  at  base.     Mass.,  N.  Y. 

Always  found  floating,  in  company  with  filamentous  algae  of 
various  kinds.  It  is  of  course  probable  that  it  is  attached  at 
some  early  stage,  but  this  has  not  been  observed. 

13.  S.  SUBSECUNDUM  Kutziiig,    1843,   p.  253;    Wolle,  1887, 
p.    112,    PL   XCIX,    fig.   2?;    Myxonema  subsecundum    Hazen, 
1902,   p.  207,  PI.  XXXVI,  fig.  3.     Forming  loose,  pale  green 
or  yellowish  tufts;  filaments  elongate,  sparingly  branched,  12- 
18,  usually  16  n  diam.;  cells  3-10  diam.  long;  branches  never 
opposite  ;  some  branches  elongate  like  the  main  stem,  others 
shorter;  cells   2-3  diam.  long  ;  all  branches  attenuate  towards 
the  apex;    cells  cylindrical,  or  dissepiments  very  slightly  con- 
stricted.    In  ditches.     N.  J.,  So.  Carolina,  Jamaica.       Europe. 

A   soft,    pale   green   plant,    especially   characterized   by  the 


302  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

scanty  ramification  and  the  strongly  tapering  branches  resem- 
bling .S.  stagnatile,  but  with  larger  cells,  branches  never  opposite, 
forming  dense  tufts ;  never  found  in  a  floating  state. 

14.  S.  minus  (Hansg.)  uov.  comb.;  5".  longipilus  var.  minus 
Hansgirg,  1886,  p.  227  ;  P.  B.-A.,  No.  865.  Forming  dense 
tufts  up  to  5  mm.  high  ;  filaments  radiating  from  a  palmelloid 
base,  4-6  fj.  diam.,  cells  2-4  diam.  long  ;  filaments  sparingly  and 
irregularly  branched,  ending  in  a  long  hair  ;  procumbent  fila- 
ments arising  near  the  base  of  the  erect  filaments,  similar  or 
slightly  larger.  Mass. 

This  plant  was  found  growing  on  stems  of  plants  in  a  clay-pit, 
Medford,  Mass.,  June,  1900.  It  seems  to  be  the  S.longipilus 
var.  minus  of  Hansgirg,  but  as  pointed  out  by  Hazen,  5".  longi- 
pilus  is  a  plant  of  much  larger  dimensions.  The  small  form 
seems  to  continue  of  the  same  size,  not  to  pass  into  the  typical 
^S".  longipilus. 

25.     DRAPARNALDIA  Bory,  1808,  p.  399. 

Filaments  united  by  a  soft,  gelatinous  coating,  not  forming  a 
thallus  of  definite  form  ;  main  filaments  attached  by  basal  rhi- 
zoids,  more  or  less  branched,  stout,  bearing  dense  lateral  fas- 
cicles of  ramuli,  much  smaller  than  the  main  filaments,  often 
setiferous.  Chromatophore  in  the  stem  and  large  branches  a 
parietal  band,  sometimes  perforated,  with  numerous  pyrenoids  ; 
in  the  cells  of  the  ramuli,  a  layer  covering  the  wall,  with  few 
pyrenoids.  Asexual  reproduction  only  from  the  ,cells  of  the 
ramuli,  by  4-ciliate  zoospores  with  red  stigma,  germinating  im- 
mediately ;  also  by  akinetes  and  aplanospores ;  sexual  repro- 
duction by  conjugation  of  4-ciliate  gametes,  which,  however, 
may  germinate  without  copulation. 

Common  plants  of  running  water,  chiefly  in  spring  ;  distin- 
guished from  Stigcoclonium  and  Chaetophora  by  the  sharp  con- 
trast between  the  main  stems  and  the  ramuli ;  also  from  Chacto- 
bhora  by  the  thin,  amorphous  character  of  the  gelatinous  coating. 

KEY  TO  THE  SPECIES  OF  DRAPARNALDIA. 

i.     Rachis  of  the  fascicle  of  ratnuli  distinct  throughout.  2. 

i.     Rachis  of  the  fascicle  of  ramuli  indistinct.  3. 

2.     Fascicles  erect,  lanceolate,  elongate.  i.     D.plumosa. 

2.     Fascicles  spreading,  broadly  ovate,  acuminate.  2.     D.  acuta. 

3.     Cells  of  main  branches  inflated,  chromatophore  narrow. 

3.     D.  glomerata. 
3.     Cells  of  main  branches  cylindrical,  chromatophore  broad. 

4.     D.  platyzonata. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  303 

i.  D.  PLUMOSA  (Vauch.)  Agardh,  1812,  p.  42;  Harvey, 
1858,  p.  72;  Wolle,  1887,  p.  109,  PI.  XCIV;  Hazen,  1902,  p. 
218,  PI.  XL,  figs,  i  and  2;  P.  B.-A.,  Nos.  21,  1224.  Tufts  up 
to  15  cm.  long,  branches  spreading  or  ascending,  solitary  or 
opposite,  fascicles  of  ramuli  single,  opposite,  or  whorled,  usually 
erect,  dense,  lanceolate  or  ovate-acuminate  in  outline,  with  pro- 
longed percurrent  rachis ;  ramuli  erect  or  ascending,  subulate 
or  setiferous  ;  cells  of  main  filaments  and  branches  subcylindri- 
cal,  45-70  /A  diam.,  1-3  diam.  long;  ramuli  6-10  /*  diam.,  1-4 
diam.  long;  chromatophore  occupying  ^-^  the  length  of  the 
large  cells,  proportionately  broader  in  the  smaller  cells.  Ver- 
mont to  California.  Europe. 

A  widely  distributed  and  fairly  common  species ;  its  most 
distinctive  character  is  found  in  the  dense,  plumose  fascicles  of 
ramuli,  acuminate  in  outline,  with  percurrent  rachis. 

2.  D.  ACUTA  (Ag.)  Kiitzing,   1845,  p.  230;   1853,  PI.  XIII, 
fig.  2;   Hazen,  1902,  p.  219;   P.  B.-A.,   No.  1072.     Tufts  up  to 
10  cm.  long,  branches  spreading  or  ascending,  solitary  or  oppo- 
site, fascicles  of  ramuli  single,  opposite,  or  whorled,  somewhat 
dense,  ascending  or  spreading,  broadly  ovate  to  lance-ovate  and 
acuminate  in  outline,  rachis  usually  distinct ;  ramuli  ascending, 
often  curved,   subulate  or  setiferous  ;  cells  of  larger  branches 
somewhat  inflated,   or  nearly  cylindrical   above,    50-90,    rarely 
no  fj.  diam.,  1-2  diam.  long;  chromatophore  not  over  half  the 
the  cell  length  in  width  ;  ramuli  6-10  p.  diam.     Mass,  to  N.  J., 
Oregon.  Europe. 

Quite  close  to  D.plumosa,  and  perhaps  only  a  variety,  but 
usually  with  larger  stems,  branching  more  spreading,  fascicles 
of  ramuli  broader  in  outline. 

3.  D.  GLOMERATA  (Vauch.)  Agardh,   1812,  p.  41  ;  Harvey, 
1858,  p.  72  ;  Wolle,   1887,  p.    108,   PI.  XCII ;  Hazen,  1902,  p. 
220,  PI.  XL,  figs.  3  and  4;  P.  B.-A.,   No.  20.     Tufts  usually 
dense,    up   to  8  cm.  long ;  filaments  much  branched,  branches 
spreading  or  horizontal,  solitary  or  opposite,   moniliform,  bear- 
ing very  numerous  scattered,  opposite,  or  whorled  fascicles  of 
ramuli ;  fascicles  mostly  set  at  right  angles  to  the  stem  and 
sessile,  broadly  orbicular  to  elliptical,  rachis  indistinct,  ramuli 
spreading,   crowded,   subulate,   often  long-setiferous ;    cells  of 
main  branches  much  swollen,  50-90  or  even   125  p.  diam.,  ^-2 
diam.  long;  chromatophore  here  not  over  half  as  broad  as  the 
length  of  the  cell,   but  proportionally  broader  in  the  smaller 
branches;  ramuli  6-9  /x  diam.     Fig.  89.     Maine  to  N.  J.,  Minn., 
Cal.  Europe. 


304  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

A  very  common  spring  plant  in  brooks,  etc.,  varying  consid- 
erably in  appearance,  but  easily  recognized.  At  first  it  is  deep 
green,  but  becomes  quite  pale  later  in  the  season,  the  empty 
cells  remaining  after  the  escape  of  the  zoospores. 

4.  D.  PLATYZONATA  Hazen,  1902,  p.  222,  PI.  XL,!.  Loosely 
tufted,  up  to  7  cm.  long ;  branches  mostly  opposite  or  whorled, 
horizontal;  fascicles  of  ramuli  at  right  angles  to  the  stern,  dis- 
tinctly stalked,  broadly  orbicular  in  outline,  ramuli  somewhat 
symmetrically  radiating  from  the  summit  of  the  rachis  or  its 
branches,  subfusiform,  acuminate  or  setiferous ;  cells  of  the 
larger  branches  cylindrical  or  slightly  constricted  at  the  nodes, 
50-90  /u.  diam.,  i  diatn.  long  or  less;  chromatophore  very  wide, 
nearly  or  quite  filling  the  cell,  often  reticular ;  ramuli  6-n  /u, 
diam.  Vermont,  Mass.,  N.  J. 

Though  reported  from  few  localities  only,  this  seems  to  be  a 
quite  distinct  species,  and  it  will  probably  be  found  in  other 
places. 

26.     PLEUROCOCCUS  Meneghini,  1842,  p.  30. 

Cells  round,  or  angular  by  mutual  pressure,  dividing  in  all 
three  directions,  remaining  attached  in  irregular  masses  of  up 
to  32  cells  or  even  more  ;  chromatophore  in  form  of  small  grains 
or  united  to  a  disk,  with  or  without  a  pyrenoid  ;  zoospores, 
aplanospores  and  zoogametes  have  been  reported. 

P.  VULGARIS  Meneghini,  1842,  p.  38,  PI.  V,  fig.  i  ;  Nageli, 
1848,  p.  65,  PI.  IV. E,  fig.  2;  P.  B.-A.,  No.  760.  Cells  4-6  /* 
diam.,  singly  spherical  but  becoming  angular  when  in  contact, 
often  2  to  many  cells  continuing  attached.  On  wood,  stone, 
and  brick,  in  moist  or  shaded  places.  Fig.  106.  From  Greenland 
south.  Europe. 

Probably  the  nearest  to  omnipresent  of  all  the  algae,  as  it  is 
found  in  practically  every  station,  not  submerged,  where  moist- 
ure is  occasionally  to  be  had.  It  forms  the  thin  green  coating 
found  on  stone  walls,  buildings  and  trees,  especially  on  the 
north  side  ;  this  preference  for  the  north  side  of  trees  is  usually 
so  marked  that  one  can  determine  the  cardinal  points  of  the 
compass,  except  in  dense  woods.  It  is-  found  as  far  north  as 
Greenland  ;  whether  it  has  a  southern  limit,  going  towards  the 
equator,  is  not  certain. 

It  forms  a  somewhat  friable  coating  in  dry  weather,  becoming 
gelatinous  in  rain  ;  the  cells  may  separate  promptly  after  divid- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  305 

ing,  but  oftener  continue  attached  in  larger  or  smaller  numbers, 
the  families  of  no  definite  form,  sometimes  seeming  like  the  be- 
ginning of  filaments  ;  spores  of  various  species  of  algae  may  be 
found  germinating  in  company  with  Pleurococcus,  and  it  is  not 
always  easy  to  distinguish  them.  Miss  Julia  W.  Snow  has  pro- 
posed, 18993,  p.  189,  a  genus  Pscudo- Pleurococcus,  with  two 
species,  P.  botryoidcs  and  P.  vulgaris,  but  as  pointed  out  by 
Chodat,  1902,  the  characters  on  which  the  new  genus  is  founded 
belong  also  to  Pleurococcus  vulgaris. 

There  is  little  or  no  agreement  among  writers  on  algae  as  to 
what  should  be  included  in  this  genus  other  than  P.  vulgaris  ; 
taken  in  a  broad  sense  it  will  include  in  whole  or  in  part  Proto- 
coccus,  Cystococcus,  Chlorococcum ,  Chlorosphaera  and  Pseudopleuro- 
coccus.  So  little  is  known  as  to  American  forms  that  might  be 
placed  in  these  genera,  that  only  a  mention  need  be  given  of 
such  forms,  with  a  reference  that  will  indicate  where  to  look  for 
fuller  particulars. 

P.  KutzingiiQ.  S.  West,  1905,  p.  287,  PI.  CCCCLXIV,  figs. 
9  and  10,  from  Barbados,  is  said  by  the  author  to  be  at  once 
distinguishable  from  P.  vulgaris  by  the  small  size  of  the  cells, 
and  by  the  yellow-green  color.  The  diameter  given,  however, 
3.8-5.7  /A,  differs  little  from  what  we  have  noted  for  P.  vulgaris, 
and  the  shade  of  green  in  the  latter  varies  under  varying  condi- 
tions of  moisture  and  light. 

P.  regularis  Artari,  reported  in  plankton  of  Lake  Erie,  Snow, 
1903,  p.  381,  PL  II,  fig-  IX,  is  a  problematical  form,  referred 
by  Chodat  to  Codastrum,  by  Oltmanns  to  Chlorella  Beyerinck, 
itself  a  doubtful  genus,  claiming  to  include  beside  the  present 
species,  the  species  included  in  this  work  under  Palmellococcus 
and  Zoochlorclla. 

P.  aquaticns  Snow,  1903,  p.  383,  PL  III,  fig.  X,  appearing  in 
laboratory  cultures,  must  remain  uncertain,  as  long  as  nothing 
is  known  of  it  in  a  natural  condition. 

Chlorosphaera  lacustris  Snow,  1903,  p.  386,  PL  IV,  fig.  XIV, 
and  C.parvu/a  Snow,  I.e.,  p.  386,  PL  IV,  fig.  XV,  must  also 
be  considered  questionable. 

Protococcus  ovalis  Hansgirg  in  Foslie,  1890,  p.  159,  PI.  Ill, 
fig.  12.  Another  doubtful  form;  occurring  in  clefts  of  rocks 


3o6          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

near  high  water  mark  in  Norway,  and  in  a  similar  station  on 
the  coast  of  Maine.  The  cells  are  ovoid  or  ellipsoid,  S-ioXQ-^ 
/A,  with  thin  wall  and  yellow-green  contents,  solitary  or  in  a 
formless,  not  very  mucilaginous  layer. 

27.     UROCOCCUS  Kiitzing,  1849,  p.  206. 

Cells  spherical,  solitary,  originally  green,  changing  to  some 
shade  of  red  or  yellow,  with  large,  granular,  bell-shaped  chro- 
matophore  and  no  pyrenoid  ;  wall  thick,  lamellate,  the  older 
layers  ultimately  breaking  at  one  side,  but  remaining  attached 
at  the  other,  forming  a  stipe-like  prolongation,  of  about  the 
same  breadth  as  the  cell. 

A  somewhat  doubtful  genus,  which  may  ultimately  be  ab- 
sorbed in  Gloeocystis ;  it  is  represented  in  America  by  three 
forms,  which  have  been  described  as  species,  but  their  distinct- 
ness is  certainly  open  to  question. 

KEY  TO  THE  SPECIES  OF  UROCOCCUS. 

i.     Marine.  3.     U.  Foslieanus. 

I.     Fresh  water.  2. 

2.     Cells  6-15  fj.  diam.  i.     U.  Hookerianus. 

2.     Cells  25-50  fj.  diam.  2.     U.  insignis. 

1.  U.  HOOKERIANUS  (Hass.)  Kiitzing,  1849,  p.  206;  Wolle, 
1887,  p.  201,  PI.  CXXIII,   fig.    13  ;  Haematococcus  Hookeiianus 
Hassall,   1845,  p.   325,   Pi.   L,XXX,  fig.   4.      Cells  globose  or 
ellipsoid,  6-13  /A  diam.,  blood-red  when  mature  ;  stipe  densely 
annulate,  often  forked.     Pa.  Europe. 

2.  U.  INSIGNIS  (Hass.)  Kiitzing,  1849^.  207;  Wolle,  1887, 
p.  201,  PL  CXXIII,  figs,    ii   and   12;  Phyk.  Univ.,  No.  82; 
Haematococcus  insignis  Hassall,  1845,  p.  324,  PI.  L,XXX,  fig.  6. 
Cells  globose,  23-53  P  diam.,  or  including  thick,  lamellate  wall, 
up  to  70  /u,  diam.,  brownish,  orange-yellow  or  brick-red  when 
mature.     Mass.,  Pa.,  Alaska,  Vancouver.  Europe. 

In  early  stages  like  a  Gloeocystis,  with  cells  3-5  /u.  diam.  ;  in- 
creasing in  size  and  number  of  cells,  but  continuing  in  gelati- 
nous colonies  until  the  cells  are  about  io/Adiam.,  when  they 
become  free  and  develop  the  annular  wall  and  later  the  stipe. 
The  species  has  been  studied  by  Richter,  1886,  and  it  would 
seem  that  the  formation  of  the  stipe  does  not  occur  until  the 
period  of  active  vegetation  is  past ;  for  the  greater  part  of  its 
existence  the  species  develops  as  a  Gloeocystis. 

3.  U.  FOSLIEANUS  Hansgirg   in    Foslie,   1890,  p.   156,   PI. 
Ill,  figs.  4-6.     Marine;  cells  8-18  /*  diam.,  green,   becoming 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  307 

dull  orange;  diam.,  including  wall,  15-25  //. ;  stipe  rather  short, 
distinctly  annulate.  Growing  among  various  algae,  mostly  blue- 
green,  in  crusts  near  high  water  mark.  Fig.  105.  Me.  Europe. 

Much  like  U.  insignis,  and  perhaps  rather  to  be  considered  a 
small  marine  form  of  that  species  ;  in  its  early  stages  not  unlike 
Glococystis  zostericola . 

Yar.  FERRUGINEUS  Lagerheim,  1882,  p.  75,  PI.  Ill,  figs.  31- 
33.  Rusty  yellow  ;  larger  than  the  type,  up  to  90  p.  with  wall. 
Greenland.  Northern  Europe. 

28.     DACTYLOTHECE  Lagerheim,  1883,  p.  64. 

Cells  cylindrical  or  oblong-ellipsoid,  straight  or  slightly 
curved,  with  rounded  ends,  solitary  or  2-4  united  into  a  family, 
with  broad,  lamellate,  persistent  membrane ;  chromatophore 
parietal,  occupying  ^3  of  the  cell  wall,  without  pyrenoid ; 
asexual  reproduction  by  division  in  one  direction  only.  Fresh 
water. 

Like  Glococystis,  except  for  cell  division  being  in  one  direction 
only,  with  consequent  difference  in  the  shape  of  the  cells  and 
families  ;  reproduction  by  zoospores  and  akinetes  has  not  been 
observed. 

D.  CONFLUENS  (Kiitz.)  Hansgirg,*  1888,  p.  140;  Gloeothece 
con^ucus  Nageli,  1848,  p.  58,  PI.  I.G,  fig.  i  ;  Wolle,  1887,  p.  325, 
PI.  CCX,  fig.  6;  Phyk.  Univ.,  No.  483^  Cells  1.5-2.5/4  diam., 
1/4-3  diam.  long,  with  ample  membrane,  in  few-celled  families, 
10-15  p.  diam.  Forming  a  gelatinous,  yellowish  or  flesh-colored 
layer  on  rocks.  Fig.  118.  Mass.  Europe. 

29.     GLOEOCYSTIS  Nageli,  1848,  p.  65. 

Cells  spherical,  with  bell-shaped  chromatophore,  covering 
most  of  the  cell  wall,  and  one  pyrenoid  ;  wall  thick,  more  or  less 
lamellate;  asexual  reproduction  by  repeated  cell  division,  sev- 
eral generations  of  cells  often  remaining  enclosed  in  the  original 
mother  cell  wall,  and  the  walls  of  the  intermediate  generations  ; 
also  by  biciliate  zoospores,  and  by  akinetes. 

A  genus  very  closely  resembling  in  appearance,  cell  division, 
etc.,  the  blue-green  Gloeocapsa  ;  differing  in  structure  and  color 
of  contents  and  by  the  formation  of  zoospores  ;  the  latter  have, 

*The  attribution  of  this  name  to  Hausgirg  may  be  open  to  question,  as 
he  does  not  actually  use  the  binomial.  His  words  are  "  Zu  dieser  Gat- 
tung  diirfte  Gloeothece  conflnens  (Ktz.)  Nag.,  (Gloeocapsa  confluens 
Ktz.)  in  Rabh.  Alg.  Exsicc.,  No.  1231,  und  wahrscheinlich  auch  uoch 
Gloeothece  distans  Stiz.  gehbren."  There  seems  hereto  be  involved,  in 
addition  to  the  usual  rules  of  nomenclature,  the  question  as  to  the  exact 
signification  of  a  German  auxiliary  verb. 


308          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

however,  been  observed  in  only  a  few  species  ;  other  species 
have  been  passed  back  and  forth  between  the  two  genera  ;  the 
chief  difficulty  is  not  in  knowing  whether  an  alga  under  exam- 
ination belongs  to  the  Chlorophyceae  or  to  the  Cyanophyceae, 
but  in  knowing  whether  the  long  lost  original  of  a  scanty  specific 
description  belonged  to  one  or  the  other.  Fresh  water  and 
marine. 

It  is  quite  probable  that  supposed  species  of  this  genus  are 
merely  stages  of  other  algae,  like  the  "  Palmella-stage  "  ;  others 
seem  to  be  permanent,  and  not  connected  with  any  other  organ- 
ism. The  only  sure  test  would  be  prolonged  cultures  under 
varying  conditions  ;  but  observations  for  a  series  of  years  of  G. 
vesiculosa  and  G.  rupestris,  in  a  state  of  nature,  have  shown 
great  uniformity.  Other  species  are  here  included  which  seem 
fairly  well  marked. 

KEY  TO  THE  SPECIES  OF  GLOEOCYSTIS. 

i.     Marine.  6. 

i.     Fresh  water.  2. 

2.     Cells  not  over  6  M  diam.  3. 

2.     Cells  6-12  /u  diam.  4. 

3.     Forming  a  soft  coating,  or  scattered  among  other  algae.  5. 

3.     Forming  a  firm,  cartilaginous  layer.  4.     G.  Paroliniana. 

4.     Cells  6-8  /u.  diam.,  bright  green.  i.     G.  vesiculosa. 

4.     Cells  9-12  fj.  diam.,  more  or  less  brownish.  3.     G.  gigas. 

5.     On  pottery  and  glass  in  greenhouses.  6.     G.fenestralis. 

5.     On  wet  rocks.  2.     G.  rupestris. 

6.     Cells  averaging  over  15  p.  diam.  5.     G.  zostericola. 

6.     Cells  averaging  4-6  /*  diam.  7.     G,  scopulorum. 

1.  G.  VESCICULOSA  Nageli,  1848,  p.  66,  PI.  IV. F. ;  Wolle, 
1887,   p.  196,  PI.  CLXVI,  figs.  9-15  ;  P.  B.-A.,  No.  609.     Cells 
bright  green,   globose  or  flattened,  solitary  or  2-8    forming  a 
family    16-35   f-    diam.;    membrane    soft,    hyaline,     lamellate; 
among  other  algae,  on  wet  rocks,  etc.,  rarely  forming  a  distinct 
stratum.     Me.,  Mass.  Europe. 

2.  G.  RUPESTRIS  (Lyngb.)  Rabenhorst,  1863,  p.  128  ;  Wolle, 
1887,  p.  196,  PI.  CLXVI,  figs.  19-21  ;  P.  B.-A.,  No.  608.     Cells 
green,   globose,   3-5  //.  diam.,  solitary  or  4-12  forming  a  family 
12-60  p.  diam.  ;  membrane  soft,  hyaline,  lamellate,  quite  wide. 
Greenland,  Mass.  Europe. 

In  the  same  stations  as  G.  vesiculosa ,  and  often  in  company 
with  the  latter  ;  distinguished  by  the  smaller  cells,  more  in  a 
family,  with  relatively  wider  membrane. 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  309 

3.  G.  GIGAS  (Kiitz.)   I.agerheim,  1883,  p.  63;  Phyk.  Univ. 
No.  638  ;   G.  amp/a  Wolle,    1887,  p.    196,  PI.   CLVI,   figs.   2-8. 
Cells  globose  or  oblong-ellipsoid,  9-12  p.  diam.,  solitary  or  2-8 
forming   a    family    45-95  p.  diam.  ;    membrane  thick,  distinctly 
lamellate  ;  contents  green,  but  containing  brownish  oil  globules  ; 
forming  gelatinous,  roundish,  dull  green  or  brownish  masses  on 
submerged  objects.     Me.,  Mass.,  W.  I.  Europe. 

When  the  brownish  oil  drops  are  abundant,  it  is  called  var. 
mfcsccns,  but  the  distinction  is  not  worth  a  name. 

4.  G.  PAROI.INIANA  (Menegh.)  Nageli,  1848,  p.  65  ;  Phyk. 
Tniv.,   Nos.  23,  597  ;  Microcystis  Paroliniana  Meneghini,  1842, 
p.  78,  PI.  X,  fig.  2.     Cells  3-6  p.  diam.,  globose,  2-8  forming  a 
family  not  over  24  p.  diam.;  membrane  hyaline,  lamellate  ;  con- 
tents yellowish  ;  forming  a  firm  incrusting  stratum  on  wet  rocks, 
etc.,  about  2  mm.  thick.     Mass.,  N.  H.,  Canada.  Europe. 

Distinguished  by  the  yellowish  color,  and  the  small  families 
united  into  a  firm  stratum. 

5.  G.   zostericola   (Farlow)   nov.  comb.;    Gloeocapsa  zosteri- 
cola   Farlow,    1882,  p.  68  ;    Gloeocystis  chrysophthalma  P.  B.-A., 
No.    219.      Marine;    cells   spherical   or    by    mutual    pressure 
flattened-hemispherical,   19-26X9-11    p-,    2-4   united   to   form   a 
family  40-100  p.  diam.;  membrane  ample,  lamellate;    contents 
brownish;  forming  brownish  masses  on  Zostera  marina.    Wood's 
Hole,  Mass.;  has  not  been  observed  elsewhere. 

6.  G.  FENESTRAIJS  (Kiitz.)  A.  Braun  in  Wittr.  and  Nordst., 
Alg.   Exsicc.,   No.  444;  P.  B.-A.,   No.  566;   Gloeocapsa  fenes- 
tralis  Kiitzing,  18493,  PI.  XV,  fig.  5.     Cells  globose  or  oblong, 
2-4.5  /*  diant.,  with  membrane  7-15  p.,  solitary  or  2  18  forming  a 
family,    15-50  p.   diam.;  membrane   hyaline,    thick,    lamellate, 
chromatophore  bright  green  ;  forming  a  thin,  soft,  pale  or  yel- 
lowish stratum  in  greenhouses,  etc.     Mass.,  R.  I.  Eiirope. 

7.  G.  SCOPULORUM  Hansgirg  in  Foslie,   1890,  p.  155^  Col- 
lins, 19083,  p.  155.     Cells  4-6  p.  diam.,  united  in  colonies  of  2-8 
cells,    envelop    distinctly   stratified ;    forming    greenish-yellow 
gelatinous  masses   in  company  with  other  minute  algae,  near 
high  water  mark.     Me.  Europe. 

A  doubtful  species  ;  possibly  a  state  of  Ulothrix  or  Urospora. 
30.  GLOIOCOCCUS  A.  Braun,  1851,  p.  170. 

Cells  globose,  enclosed  in  greater  or  less  number  in  an  ample 
globular  transparent  gelatinous  mass  ;  with  bell-shaped  chroma- 
tophore and  one  pyrenoid.  Asexual  reproduction  by  division 
of  a  cell  into  four  daughter  cells,  by  the  formation  of  aplano- 
spores,  and  by  the  formation  of  biciliate  zoospores,  of  two  sizes. 


310          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

G.  MUCOSUS  A.  Braun,  1851,  p.  170;  P.  B.-A.,  No.  1516; 
Sphaerocystis  Schroeteri  Chodat,  1897,  p.  292,  PI.  IX.  Cells 
6-10  /x  diain.,  colonies  50-1200  /x,  perfectly  spherical  and  trans- 
parent. Common  in  plankton  of  quiet  fresh  water.  Fig.  122. 
Me.,  Mass.  Europe. 

31.  GLOEOTAENIUM  Hansgirg,  1890,  p.  10. 
Cells  globose,  subellipsoid,  or  flattened,  united  in  flattened, 
rounded  families  of  2  or  4  cells,  with  wide  and  distinctly  lamel- 
late gelatinous  walls;  chromatophore  a  somewhat  curved  disk, 
with  no  pyreuoid  ;  each  family  encircled  by  one  or  more  dark- 
colored,  opaque  rings. 

Little  is  known  in  regard  to  the  reproduction  in  this  genus, 
but  it  is  probably  similar  to  that  in  Gloeocystis  ;  the  only  notice- 
able difference  between  the  two  genera  is  found  in  the  peculiar 
dark  bands,  whose  nature  is  imperfectly  known.  Only  one 
species. 

G.  LOITLESBERGERIANUM  Hansgirg,  1890,  p.  10 ;  G.  S. 
West,  1905,  p.  288,  PI.  CCCCLXIV,  figs.  22  and  23.  Cells 
15-24X18-21  p.,  united  in  2  or  4-celled  families;  in  2-celled 
families,  including  teguments,  42-70X28-40  /x,  24-30  tt  thick  ;  in 
4-celled  families  60-80X40-60 /x,  30-40 /x  thick  ;  2-celled  family 
encircled  by  one  opaque  band,  10-30  /x  wide  ;  4-celled  family  by 
two  such  bands,  intersecting  on  the  flat  side,  and  appearing 
cruciform  seen  from  that  side.  In  still  water  among  other 
algae.  Fig.  109.  Trinidad.  Europe. 

32.     PALMODICTYON  Kiitzing,  1845,  p.  155. 

Cells  similar  to  those  of  Gloeocystis ;  families  of  1-3  genera- 
tions included  in  a  wide,  gelatinous  wall  ;  combined  into  a  gelat- 
inous, subcylindrical  thallus,  more  or  less  branching  and  anas- 
tomosing ;  reproduction  by  akinetes. 

Differs  from  Gloeocystis  by  the  combination  of  the  families  into 
a  gelatinous  thallus  of  definite  shape. 

P.  VIRIDE  Kiitzing,  1845,  p.  155  ;  West,  1904,  p.  247,  fig. 
115.  Cells  5-9  ti  diam.,  families  up  to  5oyu.diam.;  thallus  i- 
several  families  wide,  up  to  2  mm.  long,  branching  and  anasto- 
mosing freely,  the  outer  layer  often  more  or  less  reddish.  Fig. 
107.  Mass.  Europe. 

Family  7.     HERPOSTEIRACEAE. 

Vegetative  characters  and  asexual  reproduction  as  in  the 
Chaetophoraceae ;  sexual  reproduction  by  antheridia  and 
oogonia  transformed  from  vegetative  cells ;  oospore  spherical , 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  311 

large,  with  four  cilia,   which  disappear  before  fertilization  by 
the  smaller,  pyriform,  4-ciliate  spermatozoids.     Only  one  genus. 

HERPOSTEIRON  Nageli  in  Kiitzing,  1849,  p.  424. 

Frond  microscopic,  epiphytic,  composed  of  simple  or  irregu- 
larly branched  filaments ;  cells  bearing  on  the  upper  surface 
long,  hyaline,  inarticulate  setae,  with  bulbous  base  but  no 
sheath  ;  chromatophore  parietal,  with  one  or  more  pyrenoids. 
Asexual  reproduction  by  4-ciliate  zoospores  with  red  stigma, 
1-4  in  a  cell ;  sexual  reproduction  by  the  union  of  a  spermato- 
zoid  and  an  oospore,  both  4-ciliate. 

The  forms  included  under  Hcrpostciron  and  Chaetosphaciidimn 
have  all  been  included  by  authors  under  Aphanochaete,  a  generic 
name  which  apparently  must  be  given  up.  Detailed  reasons  for 
this,  as  well  as  an  account  of  the  confusion  in  specific  nomen- 
clature, will  be  found  under  Herposteiron  in  Hazen,  1902. 

KEY  TO  THE  SPECIES  OF  HERPOSTEIRON. 

i.     Cells  usually  subglobose,  5-10  M  diain.  i.     H.  confervicola. 

i.     Cells  usually  subcyliudrical,  4-6  fj.  diam.  2.     H.  vermiculoides. 

1.  H.    CONFERVICOLA    Nageli    in    Kiitzing,    1849,    p.    424; 
Hazen,  1902,  p.  230,  PI.  XL,II,  figs.  5-7;  Aphanochaete  repens 
Wolle,  1887,  p.  119,  PI.  CV,  fig.  8  ;   P.  B.-A.,  No.  762.     Creep- 
ing on  various  fresh  water  algae,  filaments  irregularly  torulose  ; 
cells  subglobose  to  nearly  cylindrical ;  setae  more  or   less  fre- 
quent, about  3-4  p.  diam.  at  base,  very  slender  above,  up  to  200 
p.  long.     Fig.  116.     Greenland,  Vt.  to  N.  Y.,  Cal.  Europe. 

Probably  not  uncommon,  but  visible  only  on  microscopic  ex- 
amination of  the  host.  The  setae  are  not  as  uniformly  produced 
as  in  Bolbocoleon  and  Chaetosphacridium  ;  often  only  a  small  pro- 
portion of  the  cells  are  provided  with  them. 

2.  H.    vermiculoides    (Wolle)    nov.    comb.;    Aphanochaete 
vermiculoides  Wolle,    1887,   p.  119,   PI.   CV,  figs.  9  and   10  ;   P. 
B.-A.,  No.  161.     Cells  4-6  ^  diam.,  about   as   long   as  broad, 
more  or  less  rounded,  single  or  united  in  filaments,  creeping  on 
larger  algae,  or  attached  at  two  or  more  points,  arched  between  ; 
setae  few  or  many,  seldom  over  50  yu.  long,  with  ellipsoidal  base, 
one,  rarely  two  or  three  from  a  cell,  often  absent.     On  Zygnema, 
Hyalotheca,  etc.     Conn.,  Pa. 

Nothing  being  known  of  the  reproduction,  the  position  of  this 
plant  is  doubtful.  The  shape  of  the  filaments  is  singular,  often 
reminding  one  of  a  canker  worm  or  measuring  worm  in  motion. 
Apparently  the  filament,  attached  in  two  places,  grows  so 


312  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

rapidly  between  these  points  that  it  forms  an  arch.  Wolle's 
figure  is  unsatisfactory,  giving  no  idea  of  the  form  of  the  cells  or 
of  the  setae,  and  not  showing  the  manner  in  which  the  filaments 
encircle  the  host. 

Family  8.     COL,EOCHAETACEAE. 

Frond  consisting  of  dichotomously  branched,  monosiphonous 
filaments ;  all  prostrate  on  the  substratum,  or  with  erect 
branches,  branches  distinct  or  laterally  united  to  form  a  disk, 
or  a  pulvinate  mass  ;  growth  by  division  of  terminal  cells  only  ; 
cells  uninucleate,  with  a  parietal  chromatophore,  covering 
nearly  all  the  cell  wall  and  one  pyrenoid,  often  producing 
slender,  sheathed  setae ;  asexual  reproduction  by  biciliate  zo- 
ospores  without  stigma,  produced  one  in  a  cell,  escaping  by  an 
opening  in  the  wall,  and  germinating  directly  ;  sexual  repro- 
duction by  oogonia  and  antheridia,  produced  in  some  species 
on  the  same  individual,  in  some  species  on  separate  individuals  ; 
autheridia  formed  by  the  division  of  vegetative  cells,  or  by 
outgrowths  from  them,  producing  each  one  spherical,  biciliate 
spermatozoid,  released  by  the  dissolving  of  the  cell  wall  ; 
oogonium  formed  of  the  terminal  cell  of  a  branch,  which  en- 
larges and  at  the  same  time  sends  out  a  tubular  prolonga- 
tion ;  after  fertilization  by  the  spermatozoid  this  is  closed 
by  a  partition  at  its  base,  branches  in  some  species  grow- 
ing out  from  the  cell  below  the  oogonium  or  the  neighboring 
ce'lls,  and  forming  a  more  or  less  complete  cellular  coating  to  it, 
becoming  red  or  red-brown.  The  oospore  with  its  coating  rests 
for  a  long  period,  then  the  spore  divides  and  increases  in  size, 
breaking  through  and  throwing  off  more  or  less  completely  the 
coating,  and  from  each'cell  is  produced  a  zoospore,  which  ger- 
minates and  produces  the  ordinary  plant.  Only  one  genus. 

COLEOCHAETE  Brebisson,  1844,  p.  29. 
Characters  of  the  Family. 

This  genus  represents  the  highest  type  of  fructification  among 
the  green  algae,  showing  a  considerable  likeness  to  some  of  the 
lower  forms  of  mosses,  and  possibly  also  an  approach  to  some  of 
the  Florideae.  The  fronds  of  the  various  species  form  small, 
bright  green  disks  or  cushions  on  fresh  water  plants  or  other 
submerged  objects. 

KEY  TO  THE  SPECIES  OF  COLEOCHAETE. 

i.     Forming  gelatinous  cushion-like  masses.  6. 

i.     Forming  monostromatic  expansions.  2. 

2.     Filaments  more  or  less  distinctly  radiate.  ?. 

2.     Filaments  spreading  irregularly. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  313 

3.     Filaments  laterally  united.  4. 

3.     Filaments  free.  i.     C.  soluta. 

4.     Disk  somewhat  irregular  in  outline ;    cells  usually  25  n  wide  or 

more.  4.     C.  scutata. 

4.     Disk  regularly  orbicular;  cells  seldom  over  15  M  diam. 

5.     C.  orbicularis. 

5.     Epiphytic.  2.     C.  irregularis, 

5.     Endophytic.  3.     C.  Nite llaru ui. 

6.     Forming  uniformly  rounded  masses ;  filaments  radiating  from  the 

center.  6.     C.  pulvinata. 

6.     Masses  irregular ;  filaments  with  no  common  center. 

7.     C.  divergens. 

1.  C.  son'TA  (Breb.)  Pringsheim,   1860,  p.  6,  PI.  I,  figs.  2 
and  3  ;  PI.  IV,  figs,  i  and  2  ;  Wolle,   1887,  p.  64,  PI.  LXXII, 
figs.    1-7.      Filaments   branching,    radiating    from    a   common 
center,  prostrate,  not  lateralty  united;  vegetative  cells   12-25 /A 
diam.,  2-3  diam.  long ; -oogonia  at  first  lageniform,  then  glo- 
bose, corticated,  up  to  200  p.  diam.,  including  cortex;   oospore 
100-150  /A  diam.;.  antheridia   flask-shaped,  about  17  p.  diam. 
Mass.,  N.  J.  Europe. 

2.  C.  IRREGULARIS  Pringsheim,   1860,   p.  n,   PI.  I,  fig.  6; 
PL  VI,  figs.  3-9;  Wolle,    1887,  p.  65,  PI.  LXXII,  figs.  15-16. 
Filaments  prostrate  or  decumbent,  free  or  more  or  less  united, 
quite   irregular,    not    forming  a   disk ;    cells  quadrangular  or 
polygonal,  up  to  25  p  diam.,  1-1^2  diam.  long;  oogonia  ovoid, 
either  quite  naked  or  somewhat  corticated  above,  about  120X65 
//.;  antheridia?     Pa.,  N.  J.  Europe. 

The  only  species  with  regular  outline  to  the  frond,  but  fila- 
ments not.  laterally  united. 

3.  C.  NITELLARUM  Jost,    1895,  p.  434,  PI.  XXXIV;   C.  ir- 
regularis P.  B.-A.,  No.  974,  not  Pringsheim.     Fronds  endophytic 
in  cell  wall  of  Nitclla  or  Chara ;   filaments  simple  or  branched, 
more  or  less  united  to  form  a  membranous  expansion  ;  cells  very 
irregular  in  outline,  much  flattened  ;  no  erect  branches ;  setae 
penetrating   the  wall  of   the   host   and   projecting  externally  ; 
oogonia  spherical  or  flattened,  more  or  less  corticated  above  ; 
antheridia  small  cells  cut  off  from  the  vegetative  cells,  usually  a 
number  together.     Mass.,  N.  Y.,  Neb.,  Mexico. 

Europe,  So.  America. 

Much  resembling  C.  irregularis  in  general  characters, .except 
as  modified  by  the  peculiar  habitat.  Probably  all  reports  of  C. 
irregularis  on  Chara  or  Nitclla  refer  to  this  species  ;  it  was  dis- 
tributed under  the  name  of  C.  irregularis  in  P.  B.-A.,  No.  974. 


3H     TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

4.  C.  SCUTATA  Brebisson,  1844,  p.  29,  PI.  II,  figs.  1-7;  Rab- 
enhorst,  Algen,  No.  1126  ;  Wolle,  1887,  p.  64,  PI.  L/KXII,  figs.  8- 
13.     Dioecious;    frond  orbicular,  subparenchymatous,  monostro- 
matic,  composed  of  laterally  united,  branching  filaments,  radiat- 
ing from  a  center;  cells  quadrangular,  25-45  P  diam.,  1-3  diam. 
long;  oogonia  subglobose,  naked  below,  corticated  above,  140- 
160X120  //.;  antheridia  produced  4  from  the  division  of  a  vege- 
tative cell.     Mass.,  N.  Y.,  N.  J.,  Neb.,  Colo. 

Europe,  Asia,  So.  America,  New  Zealand. 

Distinguished  from  all  but  C.  orbiculan's  by  the  continuous, 
monostromatic  frond. 

5.  C.  ORBICULARIS  Pringsheim,  1860,  p.  n,  PL  I,  fig.  5  ;  PL 
III,  figs.  6  and  7  ;   PL  VI,  figs,    i   and  2  ;  Wolle,  1887,  p.    64, 
PL  LXXII,  fig.  14.     Frond  orbicular,  parenchymatous,  mono- 
stromatic,  composed  of   laterally   united,  branching  filaments; 
cells  oblong,  quadrangular  or  polygonal,  8-i6/xdiam.,  about  2 
diam.  long;  oogonia  ovoid,  60-85X50-65  p.,  naked  below,  more 
or  less  corticated  above  ;  antheridia  not  known.     Mass.,  N.  J., 
Neb.  Europe,  New  Zealand,  Hawaii, 

Closely  resembling  C.  scutata,  but  more  regular  in  outline, 
and  with  smaller  cells  ;  if  antheridia  should  be  found  similar  to 
those  of  C.  scutata,  it  might  be  treated  as  a  variety  of  the  latter. 

6.  C.  PULVitfATA  A.  Braun  in  Kiitzing,  1849,  p.  425;   1855, 
PL  LXXXIX,  fig.  3;   Wolle,    1887,  p.  64;  P.  B.-A.,   No.   75. 
Monoecious ;  frond  pulvinate,  gelatinous,  composed  of  branch- 
ing filaments,  radiating  from  a  common  center ;  cells  20-40  /u. 
diam.,    1^-2  diam.  long;    oogonia  at.  first  lageniform,  globose 
when  mature,  corticated,  about  150/4  diam.,  including  cortex; 
oospore  iio/x  diam.;  antheridia  flask-shaped,  sessile,  near  the 
oogonia,  17  •/*  diam.,  2*4   diam.   long.     Mass.,  Pa.,  Alaska. 

Europe. 

Easily  distinguished  from  other  species  by  the  cushion-like, 
not  disk-shaped  frond,  formed  of  regularly  radiating  filaments. 

7.  C.  DIVERGENS  Pringsheim,  1860,  p.  5,   PL  I,  fig.  i  ;   PL 
II,  fig.  2.     Monoecious  ;   frond  pulvinate,  gelatinous,  composed 
of  branching  filaments,  with  no  definite  center  ;  cells  about  25  /M 
diam.,  1-3  diam.  long  ;   oogonia  including  cortex   up   to   135  p. 
diam.  ;  oospore  to  95  /x.     Fig.  no.     These  dimensions  are  for 
the  type,  which  has  not  yet  been  noted  in  America  ;  we  have 

Var.  MINOR  Hansgirg,  1886,  p.  39  ;  P.  B.-A.,  No.  1331.  Cells 
i2-i8/i  diam.,  1-2^  diam.  long;  oogonia  60-80  p.,  oospore  50- 
70  fj..  On  Batrachospermum  and  other  algae.  N.  H.  Europe. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  315 

The  pulvinate  thallus  distinguishes  this  species  from  all 
others  except  C.  pu/vinata  ;  the  absence  of  a  common  center 
for  the  filaments  from  the  latter. 

Family  9.     TRENTEPOHLIACEAE. 

Filaments  branched,  free  or  united  into  a  membrane,  cells 
uni-  or  multinucleate,  chromatophore  generally  band-shape, 
sometimes  breaking  up  into  small  disks,  without  pyrenoid  ;* 
chlorophyll  masked  by  haematochrome,  coloring  the  cells 
yellowish-,  brick-,  or  brown-red  ;  asexual  reproduction  by  bicili- 
ate  zoospores,  formed  in  sporangia  borne  on  geniculate  or 
hooked  cells ;  the  sporangia  usually  thrown  off  whole,  the 
zoospores  emitted  only  when  the  sporangia  are  moistened ; 
sexual  reproduction  by  biciliate  gametes,  formed  in  sporangia 
terminal  on  or  intercalary  in  the  vegetative  filaments ;  these 
gametes  often  germinating  without  copulation. 

Aerial  algae,  with  special  adaptations  to  this  mode  of  life. 

KEY  TO  THE  GENERA  OF  TRENTEPOHUACEAE. 
i.     Basal  layer  a  well  developed  disk  ;  erect  filaments  unbranched. 

3.    CEPHALEUROS. 
i.     Filaments  of  basal  layer  not  forming  a  disk  ;  erect  filaments  usually 

branched.  2. 

2.     Filaments  often  bearing  inarticulate  setae.  2.     NY^ANDERA. 

2.     Filaments  not  setiferous.  i.     TRENTEPOHLIA. 

i.     TRENTEPOHLIA  Martius,  1817,  p.  351. 

Basal  filaments  decumbent,  producing  erect  filaments,  simple 
or  branched,  parallel  or  irregular,  cylindrical  to  moniliform, 
colored  yellowish  to  red  with  haematochrome  in  the  living 
plant,  fading  when  dried  ;  often  with  an  agreeable  violet  odor  ; 
cells  cylindrical  to  spherical,  with  band-shaped  or  broken  chro- 
matophore and  no  pyrenoid  ;  asexual  reproduction  by  biciliate 
zoospores,  in  sporangia  borne  on  special  hooked  or  curved  cells  ; 
sexual  reproduction  by  biciliate  gametes  in  gametangia  trans- 
formed from  vegetative  cells,  lateral,  terminal,  or  intercalary, 
spherical  or  ellipsoid. 

A  genus  of  terrestrial  algae,  forming  matted  layers  on  rocks, 
and  on  leaves  and  bark  of  trees.  They  range  from  arctic  or  high 
mountain  regions  to  the  tropics ;  most  of  the  species  are  very 
variable,  and  many  species  have  been  described  based  on  charac- 
ters of  little  permanence ;  our  species  are  here  arranged  after 
Hariot,  1889-90,  quite  a  number  of  species  before  generally  rec- 
ognized being  given  as  synonyms  or  varieties.  A  curious  adap- 


316          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

tation  to  the  terrestrial  habit  of  the  genus  is  found  in  the  fact 
that  the  ripe  sporangia  frequently  are  cast  off  from  the  frond 
entire,  and  emit  the  zoospores  only  when  they  fall  into  water,  or 
are  wet  with  dew  or  rain.  The  terrestrial  habit  makes  the 
species  of  Trcntepohlia  very  accessible  to  lichen-forming  fungi, 
and  in  many  cases  it  is  rather  an  exception  to  find  a  plant  not 
,at  all  lichenized. 

KEY  TO  THE  SPECIES  OF  TRENTEPOHLIA. 

i.     Cells  cylindrical.  2. 

i.     Cells  roundish,  ellipsoid  or  fusiform.  7. 

2.     Sporangia  scattered  or  in  series.  3. 

2.     Sporangia  in  a  glomerule  or  raceme.  6. 

3.     Filaments  subsimple,  tapering,  acute.  4.     T.  effusa. 

3.     Filaments  branching,  not  tapering  nor  acute.  4. 

4.     Filaments  4-10  M  diam.  3.     T.  abietina. 

4.     Filaments  10-32 /*  diam.  5. 

5.     Filaments  usually  12-20  M,  sometimes  a  little  more  or  less. 

i.     T.  aurea, 
5.     Filaments  28-32  /*.  2.     T.  villosa. 

6.     Glomerule  terminal.  5.     T.  arborum. 

6.     Raceme  short,  lateral.  6.     T.  Wainoi. 

7.     Filaments  6-12  /u.  7.     T.  lagenifera. 

7.     Filaments  12-44  p.  8. 

8.     Growing  on  rocks,  rarely  on  mosses.  8.     T.  lolithus. 

8.     Growing  on  bark  of  trees.  9.     T.  odorata. 

8.     Growing  on  lichens.  10.     T.  rigidula. 

i.  T.  AUREA  (Iy.)  Martius,  1817,  p.  351  ;  Hariot,  1889-90, 
p.  7  ;  P.  B.-A.,  Nos.  569,  1188,  1376;  Chroolcpus  aureum  Wolle, 
1887,  p.  121,  PI.  CXV,  figs,  i -2 1.  Color  golden  to  orange, 
yellowish  when  dry  ;  basal  filaments  cylindrical  or  more  or  less 
torulose,  erect  filaments  cylindrical  or  sometimes  slightly  con- 
stricted at  the  nodes,  parallel  or  irregular,  more  or  less  branched, 
usually  obtuse  ;  forming  dense  tufts  or  extended  strata  ;  branches 
somewhat  tapering;  cells  usually  12-20 /A  diam.,  but  with  ex- 
treme forms  8-30  n  ;  membrane  either  smooth  or  roughened 
with  minute  scales  ;  gametangia  20-38  /u.  diam.,  globose  or  ellip- 
soid, terminal  or  lateral,  borne  directly  on  the  vegetative  cells ; 
sporangia  similar,  on  the  special  curved  cells. 

An  extremely  variable  species,  inhabiting  all  parts  of  the 
world  ;  characterized  by  the  cylindrical,  not  mucronate  filaments 
of  moderate  diameter,  and  by  the  solitary  or  seriate  gametangia. 
In  the  typical  form  the  membrane  is  usually  smooth,  and  the 
gametangia  scattered  ;  T.  uncinata  (Gobi)  Hariot  is  a  synonym. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  317 

Var.  POLYCARPA  (Nees  and  Mont.)  Harlot,  1889-90,  p.  15; 
T.  polycarpa,  P.  B.-A,  No.  472  ;  including  7\  Tucket  manni 
Mont.  Membrane  usually  scabrous,  gametangia  larger,  24-45  /x, 
in  long  series  ;  both  this  and  the  following  variety  pass  into  the 
type  continually.  Texas,  Cal.  So.  Atneiica. 

Var.  SUBSIMPLEX  (Caspary)  De  Toni,  1889,  p.  237;  P.  B.-A., 
No.  1377.  Krect  filaments  simple  or  with  one  or  two  short 
branches.  Cal.  Europe. 

Var.  Pittieri  (De  Wildeman)  nov.  comb.;  T.Pifdni  De 
Wildeman,  1894,  P-  6.  Filaments  18-25  /*  diam.,  smooth,  cells 
2-5  diam.  long ;  gametangia  globose  or  ovoid,  40  p.  diam.,  to  56 
P.  long,  borne  at  the  extremity  of  branches  9-12  p.  diam.,  cells 
about  4  diam.  long ;  tips  of  branches,  and  especially  of  the 
branches  bearing  gametangia,  often  coiling  about  other  filaments 
of  the  frond ;  when  this  occurs  with  the  fertile  branches,  there 
may  be  an  appearance  of  a  dense  fascicle  of  gametangia  on  the 
filament.  On  leaves  of  various  plants.  Costa  Rica. 

The  principal  characters  by  which  this  could  be  distinguished 
from  T.  an  re  a  are  the  rather  larger  and  longer  cells,  the  larger 
gametangia,  and  the  cirrhous  branches  ;  but  in  view  of  the  con- 
siderable range  of  forms  included  under  the  species,  these  char- 
acters do  not  seem  sufficient  to  distinguish  it.  The  gametangia 
are  so  designated  from  their  form  and  position,  the  original  de- 
scription designating  them  only  as  "  zoosporanges." 

2.  T.  VILLOSA  (Kiitz.)   Hariot,    1889-90,   p.  18  ;  Wittr.  and 
Nordst.,    Alg.    Exsicc.,   No.    1066.     Erect  filaments  elongate, 
tufted,  flexuous,  branching,  pellucid  ;  cells  28-30  p.  diam.,  2-2^ 
diam.  long  ;  reproduction  unknown. 

The  type  does  not  occur  with  us,  but  we  have  var.  brachy- 
meris  Hariot,  cells  28-32  p.  diam.,  48-52  p.  long.  Dominica, 
Guadeloupe,  Mexico.  Asia. 

The  cells  in  the  type  are  unusually  long  for  this  genus,  but 
shorter  in  the  variety  ;  the  diameter  is  quite  uniform  and  larger 
than  all  but  quite  exceptional  forms  of  T.  aurea. 

3.  T.  ABIETINA  (Flotow)  Hansgirg,  1886,  p.  86  ;  Wittr.  and 
Nordst.,  Alg.  Exsicc.,  No.  917;   Chroolepus  abietinum  Kiitzing, 
1854,  PI.  XCI,  fig.  2.     Forming  reddish,  more  or  less  confluent 
tufts,  becoming  ashy  when  dry  ;  cells  of  basal  layer  more  or  less 
torulose,  erect  filaments  cylindrical  or  in  a  few  of  the  lower  cells 
slightly  torulose,  .4-10  p.  diam.,  about  3  diam.  long;  terminal 
cell  sometimes  considerably  longer  ;  gametangia  on  special  cells, 


318  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

but  sometimes  terminal ;  sporangia  on  special  cells,  spherical 
or  slightly  ovoid,  12-20 /x  diam.  Canada,  N.  H.,  Vt.  Europe. 
A  northern  species  growing  usually  on  coniferous  trees,  but 
it  has  been  found  on  oaks  in  Europe.  It  is  like  the  smallest 
forms  of  T.  aurea,  but  the  filaments  are  more  delicate  and  flexu- 
ous ;  the  gametangia  are  smaller,  and  are  liable  to  be  found 
anywhere  on  either  erect  or  basal  filaments. 

4.  T.  EFFUSA  (Krempelhiiber)  Hariot,    1889-90,  p.  52,   figs. 
12  and  13;    T.  setifcra  P.  B.-A.,   No.  117.     Forming  yellowish- 
brown  patches,  becoming  whitish  when  dry ;  filaments  of  basal 
layer  cylindrical  or  more  or  less  torulose  ;  erect  filaments  120- 
300  p.  high,  6-io/xdiam.  at  the  base,  tapering  to  a  point,  usu- 
ally simple,  but  sometimes  branched  ;  cells  18-28  /x  long  ;  game- 
tangia developed  from  cells  of  the  basal  layer  or  lowest  cells  of 
the  erect  filaments,  spherical  or  ovoid,  16-20X22-30 /x.     Conn. 

Asia,  So.  America. 

The  tapering  filaments  seem  to  indicate  a  connection  between 
this  genus  and  the  Chaetophoraceae ;  we  have  no  species  for 
which  it  is  liable  to  be  mistaken. 

5.  T.  ARBORUM  (Ag.)  Hariot,  1889-90,  p.  20,  figs.  8  and  9; 
P.  B.-A.,   No.    1522.     Filaments  tufted,    elongate,   branching, 
somewhat  attenuate ;    branches  usually  patent  and   somewhat 
more  slender  than  the  main  filament;  cells  16-28 /x  diam.,  40- 
60  /x  long  ;    gametangia    usually  terminal  ;    sporangia   2-7    to- 
gether, the  branch  terminating  in  a  swollen  cell,  on  which  are 
borne  several  nearly  empty  curved  cells,  each  bearing  a  spo- 
rangium,   spherical    or-  ellipsoid,    18-24X24-32  /x.       Jamaica, 
Guadeloupe.  Asia,  So.  America,  Australia. 

The  vegetative  filaments  resemble  T.  aurea,  but  the  arrange- 
ment of  the  sporangia  is  characteristic. 

6.  T.  WAINOI  Hariot,  1889-90,  p.  19,  figs.  6  and  7  ;  P.  B.-A., 
No.  1523.     Tufts   yellow-green,  about  YI   cm.  high  ;  filaments 
cylindrical,  16-28  /x  diam.,  cells  2-4  diam.  long,  wall  smooth  and 
rather  thin,  branches  more  or  less  abundant,  irregularly  placed, 
terminal  cell  slightly  attenuate.     Gametangia  (?)  spherical,  28- 
40  /x  diam.,  in  more  or  less  close  series  along  the  fitaments  ; 
zoosporangia   (?)  about  12  /x  diam.,  borne  terminally  on  short, 
lateral  cells,  or  on  the  terminal  cells  of  branches  arising  from 
this  cell.     Fig.  117.     California,  Jamaica.  So.  America. 

7.  T.  LAGENIFERA  (Hildebrandt)  Wille,   1887,  P-  427  ;    P. 
B.-A.,   No.    1470;   Chroolepus  lagcnifcrum  Rabenhorst,   1868,  p. 
373,  fig.  104.     Frond  orange  to  crimson  ;  both  basal  and  erect 


THE  GRKKN  ALGAE  OF  NORTH  AMKKICA          319 

filaments  of  more  or  less  torulose  cells,  branching,  cells  6-12  /* 
diam.,  2-3  diam.  long;  gametangia  lageniform  to  subspherical, 
lateral  or  terminal,  sessile  or  pedicelled,  8-12  /*  diam.,  20  p.  long. 
\Y.  I.,  Cal.  Europt\  So.  America. 

The  peculiar  "  bottle-shaped  "  gametangia  are  the  character- 
istic mark  of  this  species. 

8.  T.   lorjTHus  (L.)  Wallroth,   1833,   p.   151;    Wittr.  and 
Nordst.,  Alg.  Kxsicc.,  No.  921  ;  Hariot,  1889-90,  p.  26,  fig.  14; 
Oiroolcpns  lolithus  Wolle,    1887,  p.  122,   PI.  CXVI,  figs.  9-12. 
Filaments  forming  a  thinner  or  thicker  stratum,  color  bright 
red,  becoming  olive  green  in  drying  ;  with  a  distinct  and  pleas- 
ant odor  of  violets;  erect  filaments  straight,  torulose,  branching, 
branches  curved,  apparently  dichotomous  ;  cells  swollen  at  the 
middle,  with  constricted  nodes,  14-35  /*  wide,  24-50  p  long;  a 
few  cells  at  the  end  of  the  filament  or  branch  often  cylindrical 
and  more  slender  ;  membrane  thick,  with  striations  and  other 
markings ;    gametangia   lateral,   intercalary  or  terminal  ;    spo- 
rangia round,  20-48  /*  diam.,  or  ovoid,  36-40X45-54  /*.     Me., 
Mass.,  N.  H.,  Alaska,  Cal.  Europe,  Occanica. 

A  plant  found  in  all  parts  of  the  world,  but  characteristic  of 
high  altitudes  or  latitudes ;  it  usually  grows  on  rocks,  but 
occasionally  spreads  to  the  mosses  also  growing  on  the  rocks. 

9.  T.  ODORATA  (Wiggers)  Wittrock,   1880,  p.   16  ;   Hariot, 
1889-90,  p.  29,  fig.  16;   Chroolcpus  odoratum  Wolle,  1887,  p.  122, 
PI.  CXVI,  fig.  6  ;   C.  umbrinum  Wolle,    1887,  p.   123,  in  part, 
PI.  CXVI,  figs.  4  and  5.     Filaments  forming  a  more  or  less 
dense,  brownish-  to  orange-red,  sometimes  pulverulent  or  to- 
mentose  stratum,  without  sharp  distinction  between  horizontal 
and  erect  portions,  flexuous,  with  short  branches,  more  or  less 
torulose,  cells  rounded,  ovoid,   ellipsoid  or  almost  cylindrical, 
10-30  p.  diam.,  i-i^-j  diam.  long  ;  membrane  from  thin  to  thick 
and   lamellate ;    gametangia  subspherical   to   ellipsoid,  lateral, 
terminal,  or  intercalary  ;  20-30  /*  diam.;  sporangia  of  same  size. 
Canada,  Me.,  N.  H.,   Mass.,  N.  Y.,  N.  J.,  Fla.,  Va.,  St.  Vin- 
cent, Cal.  Europe,  Asia. 

Var.  UMBRINA  (Kiitz.)  Hariot,  1889-90,  p.  36,  fig.  17  ;  T.  um- 
brina  var.  querdna,  P.'R.-A.,  No.  662.  Filaments  irregular 
and  irregularly  branched,  cells  rather  loosely  united. 

A  widely  distributed  and  variable  species,  including  a  num- 
ber of  species  of  various  authors.  Following  Hariot  we  can 
distinguish  a  typical  form,  with  cylindrical  filaments  mostly 
straight  and  parallel,  and  cells  firmly  united,  and  the  following 


320          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

varieties.  All  are  found  growing  on  bark  of  various  trees, 
rarely  on  other  objects. 

Var.  BETULINA  (Rab.)  Hariot,  1889-90,  p.  50;  P.  B.-A.,  No. 
1378.  Cells  ellipsoid,  thick-walled,  in  fairly  distinct  filaments. 
Principally  on  birch  trees.  N.  H.  Europe. 

10.  T.  RIGIDULA  (Miill.  Arg.)  Hariot,  1889-90,  p.  36,  fig. 
17;  Chroolepus  umbrinum  Wolle,  1887,  p.  123,  in  part,  PI. 
CXVI,  figs.  1-3;  C.  rigiduhim  Wittr.  and  Nordst.,  Alg. 
Exsicc.,  No.  1422.  Filaments  reddish  or  yellowish,  ascending, 
stiff,  subdichotomously  branched,  torulose,  branches  elongate  ; 
cells  fusiform-ellipsoid,  swollen,  with  strongly  constricted 
nodes,  membrane  thin,  at  first  smooth  and  pellucid,  soon  cov- 
ered with  fine  scales  or  fibrils ;  cells  16-24  P-  diam.  at  middle, 
12-15  /u.  at  nodes,  24-36/4  long  ;  gametangia  spherical,  30  \*.  diam. 
Cuba.  Asia,  New  Zealand,  So.  America. 

A  species  of  warm  regions,  always  epiphytic  on  lichens,  which 
may  be  attached  either  to  rocks  or  to  the  bark  of  trees.  It 
approaches  some  forms  of  T.  odorata,  but  is  more  branched, 
with  cells  more  moniliform,  and  with  thinner  membrane.* 

2.     NYLANDERA  Hariot,  1890,  p.  85. 

Structure  as  in  Trentepohlia,  but  all  or  many  of  the  cells  bear- 
ing inarticulate  setae.  Only  one  species. 

N.  TENTACULATA  Hariot,  1889-90,  p.  41,  fig.  22.  Tufts 
small,  inconspicuous,  brownish  when  dry  ;  prostrate  filaments 
short,  little  branched,  12-15  /*  diam.,  cells  spherical-ellipsoid, 
somewhat  torulose,  i-i}^  diam.  long;  each  cell  usually  bearing 
on  the  upper  surface  one,  rarely  two  or  three,  inarticulate  setae, 
4-5  fji  wide,  up  to  90  //,  long,  with  globose-capitate  tip.  Fig.  114. 
On  bark,  So.  Carolina. 

The  setae  clearly  distinguish  this  species  from  Trentepohlia , 
and  perhaps  indicate  an  affinity  with  the  Chaetophoraceae. 
3.     CEPHALEUROS  Kunze  in  Fries,  1829,  p.  327. 

Frond  of  a  basal  layer  of  branching  filaments,  in  one  or  more 
strata,  with  simple  erect  filaments,  terminating  either  in  a  hair, 
or  in  a  sporangium  or  group  of  sporangia,  sexual  or  asexual. 

Distinguished  from  Trentepohlia  by  the  fuller  development  of 
the  horizontal  disk,  the  reduced  development  of  the  erect  fila- 
ments and  the  presence  of  hairs. 

*  Chroolepus  moniliforme  Nageli  in  Kiitzing,  1849,  P-  895,  is  a  lichen, 
fide  Hariot,  1889-90,  p.  48.  Wolle's  plant,  1887,  p.  123,  PL  CXV,  figs. 
30-33,  appears  to  be  the  same. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  321 

C.  MYCOIDEA  Karsten,  1891,  p.  64,  PI.  IV,  fig.  n  ;  PL  V, 
fig.  i  ;  .Ifvcoidea  parasitica  Cunningham,  1879,  p.  312,  Pis. 
XLII,  XI/III,  at  least  in  part;  P.  B.-A.,  No.  763.  Frond  of 
several  layers,  attached  to  the  substratum  by  rhizoids,  with  a 
thin  general  cuticle  ;  hairs  colored  with  haematochrome  ;  very 
variable  in  shape  and  size  of  cells,  amount  of  hairs,  etc.  On 
leaves  of  various  tropical  and  subtropical  trees.  Fig.  123. 
Ja niaica .  Tropics  generally. 

Much  confusion  has  prevailed  as  to  this  species,  and  the  name 
here  used  may  not  be  in  strict  accordance  with  the  laws  of 
nomenclature  ;  but  it  seems  safe  to  use  it,  as  less  likely  to  cause 
confusion,  and  it  does  not  involve  adding  a  new  binominal  to 
the  list,  already  uncomfortably  long. 

Phyllactidium  tropicum  Mobius,  i888a,  p.  225,  PI.  VIII,  figs. 
1-15  ;  Hansgirgia  flabdligera  De  Toni,  1889,  p.  263,  is  a  doubt- 
ful form,  concerning  which  there  have  been  somewhat  contra- 
dictory reports  by  different  writers ;  it  has  been  reported  from 
Cuba  and  Porto  Rico,  and  from  most  tropical  countries.  It  is 
evidently  nearly  related  to  Ccphaleuros ;  Karsten,  1891,  p.  62, 
refers  it,  though  with  some  doubts  as  to  its  validity,  to  the 
neighboring  genus,  Phycopeltis. 

Order  V.      SIPHONOCLADIALES. 

Fronds  multicellular,  usually  more  or  less  branched ;  cells 
multi-,  very  rarely  uninucleate,  chromatophore  net-shaped,  or  of 
numerous  small  disks. 

KEY  TO  THE  FAMILIES  OP  SIPHONOCLADIALES. 
I.     Filaments  simple,  unattached  ;  sexual  reproduction  by  oospores  and 

antheridia.  5-     SPHAEROPLEACEAE. 

i.     Filaments  simple  or  branched  ;  sexual  reproduction  isogamous.     2. 
2.     Main  axis  distinct,  of  limited  growth.  3. 

2.     Main  axis  usually  indistinct ;  all  axes  of  unlimited  growth.       4. 
3.     Axis  bearing  whorls  of  branches  of  limited  growth  and  of  form  dif- 
ferent from  the  axis.  4-     DASYCLADACEAE. 
3.     Branches  either  similar  to  the  axis,  or  forming  a  terminal  tuft  or 
membrane.  3-     VALONIACEAE. 
4.     Zoospores  and  gametes  produced  in  little  changed  vegetative  cells. 

i.    CLADOPHORACEAE. 

4.     Zoospores   produced   in   distinct,  ultimately  detached   sporangia. 
Shell  boring  algae.  2.     GOMONTIACEAE. 

Family  i.     CLADOPHORACEAE. 

Frond  of  simple  or  branching,  monosiphonous  filaments,  free 
or  more  or  less  united  laterally  ;  cells  multi-,  rarely  uninucleate, 


322          TUFTS  COLLEGE;  STUDIES,  VOL.  II,  No.  3 

with  chromatophore  net-form,  or  broken  into  many  small  por- 
tions, with  many  pyrenoids ;  asexual  reproduction  by  4-ciliate 
zoospores  (sometimes  by  biciliate?)  and  by  akinetes  ;  sexual 
reproduction  by  biciliate  gametes;  zoospores  and  gametes 
formed  in  little  changed  vegetative  cells.  Marine  and  fresh 
water. 

KEY  TO  THE  GENERA  OF  CLADOPHORACEAE. 

i.     Filaments  simple.  2. 

I.     Filaments  branched:  3. 

2.     Filaments  firm,  stiff.  12. 

2.     Filaments  soft,  flaccid.  12.     HORMISCIA. 

3.     Branches  free,  not  united  to  form  a  membrane  or  tissue.  4. 

3.     Branches  united  to  form  a  membrane  or  tissue.  8. 

4.     Branches  usually  short,  rhizoidal.  2.     RHIZOCLONIUM. 

4.     Branches  of  successive  orders,  but  of  the  same  character.  5. 

5.     Partitions  regularly  at  bases  of  branches.  6. 

5.     No  partitions  regularly  at  bases  of  branches. 

5.    CLADOPHOROPSIS. 

6.     Akinetes   formed   of   swollen   intercalary  or    terminal   cells ;    zo- 
ospores unknown.  6.     PITHOPHORA. 

6.     Akinetes  unusual,  little  differentiated ;  propagation  by  zoospores. 

7- 
7.     Specialized   hooked  or  rhizoidal   branches    present ;    cell   division 

largely  intercalary.  4.     SPONGOMORPHA. 

7.     No  specialized  hooked  or  rhizoidal  branches ;  cell  division  chiefly 

terminal.  3.     CLADOPHORA. 

8.     Filaments  united  in  one  plane.  9. 

8.     Filaments  united   in   all   directions,  forming  a   solid   or  spongy 

frond.  ii. 

9.     Frond  continuous.  7.     ANADYOMENE. 

9.     Frond  perforate.  10. 

10.     Small  secondary  cells  formed  in  the  spaces  between  the  filament 

cells,  leaving  rounded  openings.  9.     CYSTODICTYON. 

10.     No  such  secondary  cells  ;  openings  angular. 

8.       MlCRODICTYON. 

ii.     Frond  a  spongy  mass  of  network.  10.     BOODLEA. 

ii.     Frond  spherical,  solid  or  hollow.  ii.     DICTYOSPHAERIA. 

12.     Filaments  regularly  cylindrical  or  clavate ;  originally  attached, 

sometimes  later  floating.  i.     CHAETOMORPHA. 

12.     Filaments  usually  more  or  less  irregular ;  not  attached. 

2.    RHIZOCLONIUM. 

i.     CHAETOMORPHA  Kutzing,  1845,  p.  203. 
Frond  of  a  single  unbranched  series  of  multinucleate  cells,  all 
but  the  usually  longer  basal  cell  capable  of  division  ;  basal  cell 
producing  either  a  disk  or  more  or  less  branched  rhizoidal  pro- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  323 

longations  for  the  purpose  of  attachment ;  frond  always  at- 
tached, or  loosening  and  continuing  in  a  free  state ;  membrane 
thick,  firm,  usually  distinctly  lamellate ;  asexual  reproduction 
by  4-ciliate  zoospores,  produced  in  little  changed  cells ;  sexual 
reproduction  by  biciliate  gametes.  Marine,  rarely  fresh  water. 

KEY  TO  THE  SPECIES  OF  CHAETOMORPHA. 

i.     Filaments  400-600  /u.  diam.  2. 

i.     Filaments  less  than  400 /a  diam.  4. 

2.     Filaments  increasing  noticeably  in  diameter  from  the  base  up. 

i.     C.  clavata. 
2.     Filaments  of  nearly  uniform  diameter  except  at  the  extreme  base. 

3- 
3.     Basal  cell  many  times  as  long  as  any  other  ;  a  southern  species. 

3.     C.  antennina. 
3.     Basal  cell  only  slightly  longer  than  the  others  ;    a  northern  species. 

2.     C,  melagonium. 

4.     Filaments  over  40  n  diam.  5. 

4.     Filaments  not  over  40  M  diam.  7. 

5.     Cells  3-8  diam.  long.  6.     C.  cannabina. 

5.     Cells  not  over  2  diam.  long.  6. 

6.     Filaments  125-400,  usually  200-250  /*  diam.,  yellowish-green. 

4.     C.  aerea. 
6.     Filaments  125-175  M  diam.,  dark  green  ;  a  southern  species. 

5.     C.  brachygona. 

7.     Filaments  attached  by  a  small  disk  ;  marine.       7.      C.  californica. 
7.     Filaments  attached  by  coralloid,  pluricellular  branches;  fresh  water. 

8.     C.  chelonnm.- 

1.  C.  CLAVATA  (Ag.)  Kiitzing,  1847,  p.  166  ;  Vickers,  1908, 
p.  17,  PI.  VII;  P.  B.-A.,  No.  371.     Filaments  erect,  stiff,  up 
to  60  cm.  long,  base  500-750  ju.  diam.,  gradually  increasing  to 
1.5  mm.  or  more  at  the  tip  ;  lower  articulations  3-4  diam.  long, 
those  of  the  upper,  part  about  as  long  as  broad,  more  or  less 
moniliform,  color  deep  green. 

Var.  TORTA  Farlow,  P.  B.-A.,  No.  571.  Fronds  loose  and 
curled,  cells  less  moniliform  than  in  the  type,  and  not  increas- 
ing in  diameter  upwards  so  noticeably. 

A  tropical  and  subtropical  species,  found  in  W.  I.  and  in 
southern  California.  In  the  latter  region  it  occurs  mostly  as 
the  variety,  corresponding  to  the  floating  forms  of  other  species 
of  the  genus. 

2.  C.  MELAGONIUM  (Web.  and  Mohr)  Kiitzing,  1845,  p.  204; 
Harvey,  1858,  p.  85;  Farlow,   1881,  p.  46;  P.  B.-A.,    No.  412 
(forma  typica)  ;  No.  413  (forma  itipincola)  ;   Conferva  melagonium 


324  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Harvey,  1846-51,  PI.  XCIX.A.  Filaments  erect,  coarse  and 
wiry,  dark  glaucous  green,  400-500  /i  diam.  ;  cells  1-2  diam. 
long. 

A  common  species  from  N.  J.  to  Greenland,  occurring  also  in 
Alaska;  two  forms  are  found;  f.  RUPINCOLA  (Aresch.)  Kjell- 
man,  growing  attached  and  erect,  usually  quite  straight,  in  low- 
est rock  pools,  and  below;  reaching  the  length  of  a  meter  in 
northern  regions,  seldom  over  a  third  of  a  meter  on  the  New 
England  coast;  f.  TYPICA  Kjellman,  unattached,  lying  loose  .in 
the  sublitoral  zone,  forming  crisped  and  entangled  masses  about 
the  roots  of  Laminaria,  etc.  ;  the  latter  form  has  usuall)"  been 
known  as  P.  Picqnotiana  Mont.,  but  is  now  pretty  generally  rec- 
ognized as  a  form  of  the  present  species.  It  seems  unnatural  to 
give  the  name  of  forma  typica  to  what  is  apparently  a  later 
stage  of  the  plant,  but  the  exigencies  of  nomenclature  require 
it.  There  is  considerable  variation  in  the  size  of  the  filaments, 
especially  in  f.  typica,  and  the  slender  forms,  sometimes  as  low 
as  300 /A  diam.,  are  not  always  easy  to  distinguish  from  C.  aerca  ; 
but  the  greater  rigidity  and  the  dark  glaucous  green  color  are 
usually  sufficient  marks.  It  is  a  favorite  host  for  epiphytes, 
and  the  number  of  species  found  growing  on  it  in  arctic  regions 
is  quite  large. 

3.  C.   ANTENNINA  (Bory)  Kiitzing,   1849,  p.  379;  Vickers, 
1908,  p.  17,   PL  VIII;  Wittr.  and   Nordst.,  Alg.  Exsicc.,  No. 
1439  ;   C,  pacifica  Kiitzing,  1849,  p.  379.     Filaments  dark  green, 
450-550  fj.  diam.,  erect,  somewhat  flexuous,  stiff  below,  less  so 
above;   articulations  2-4  diam.  long;  the  lowest  cell  8-50  diam. 
long.      W.  I.,  Atlantic  and  Pacific  coasts  of  Mexico.        Africa. 

In  habit  resembling  C.  melagoniiim  f .  mpincola  ;  distinguished 
by  the  longer  cells  and  the  very  long  basal  cell,  which  tapers 
much  at  the  base.  C.  melagonium  is  an  Arctic  species,  very 
luxuriant  in  Greenland,  only  much  reduced  forms  being  found 
south  of  Cape  Cod  ;  C.  antennina  does  not  appear  to  go  farther 
north  than  Cuba  on  the  west  and  Morocco  on  the  east  side  of 
the  Atlantic. 

4.  C.  AEREA  (Dillw.)  Kiitzing,  1849,  p.  379;  Harvey,-  1858, 
p.  86;   Farlow,   1881,  p.  46;   P.  B.-A.,  Nos.  76,  1526;   Conferva 
brachyarthra    Kiitzing,    1845,   p.   203 ;    Conferva  aerea   Harvey, 
1846-51,  PI.  XCIX.B.    Filaments  erect,  yellowish-green,  125-400 
p.  diam.,  cells  about  as  long  as  broad,  base  of  filament  usually 


THE  GREEN,  ALGAE  OP  NORTH  AMERICA  325 

more  slender  than  the  upper  part ;  when  producing  spores  the 
fertile  cells  are  much  inflated  and  nearly  globular.  Fig.  115. 

In  upper  literal,  especially  in  rock  pools,  from  Me.  to  W.  I. 
and  in  Cal.  In  habit  like  C.  melagonium,  but  of  somewhat 
smaller  diameter,  lighter  color  and  softer  texture ;  not  firm 
enough  to  stand  erect  when  taken  from  the  water. 

Forma  Linum  (Fl.  Dan.)  nov.  comb.  ;  Conferva  Linum  Har- 
vey, 1846-51,  PI.  CL.A ;  Chaetomorpha  Linum  Farlow,  1881, 
p.  47;  P.  B.-A.,  No.  22;  C.  sutoria  Harvey,  1858,  p.  87;  C. 
Olncyi  Harvey,  1858,  p.  86,  PI.  XLVI.D;  C.  Umgtarticulata 
Harvey,  1858,  p.  86,  PI.  XIvVI.E.  Filaments  unattached, 
prostrate,  light  green,  rather  stiff,  diam.  200-250  /*,  cells  about 
as  long  as  broad.  Apparently  bearing  the  same  relation  to 
typical  C.  aerea  as  the  loose  form  of  C.  melagoniiun  does  to  the 
attached  form.  It  occurs  in  great  masses  of  curled  and  crisped 
filaments  in  warm  shallow  bays,  at  least  from  N.  S.  to  W.  I. 

5.  C.  BRACHYGONA  Harvey,   1858,  p.  87,  PI.  XLVI.A;  P. 
B.-A.,    No.   622.     Filaments  free,   rigid,   curved  and   twisted, 
forming  strata  of  some  extent  on  rocks  or  among  other  algae ; 
cells  125-175  /A  diam.,  quite  uniformly  as  long  as  broad,  except 
just  after  dividing.     Fla.,  W.  I.,  Mexico. 

Usually  found  in  entangled  masses  among  other  algae,  in  the 
same  way  as  the  more  northern  Rhizoclonium  tortuosum,  which 
has,  however,  more  slender  filaments  and  proportionally  longer 
cells.  Rhizoclonium  capillare  Vickers,  1905,  p.  55,  appears  to 
belong  here. 

6.  C.  CANNABINA  (Aresch.)  Kjellman,  1889,  p.  55  ;  P.  B.-A., 
No.  916.     Filaments  unattached,  soft  and  rather  delicate,  75-100 
H  diam.,  narrow  and  wide  together  in  the  same  tuft,  or  even  a 
single  filament  tapering  from  largest  to  smallest  measurement ; 
cells  pretty  uniformly  500  to  600  /*  long,  being  from  3-8  diam.; 
color  light  green.     Me.,  Alaska,  Washington. 

Northern  Europe. 

Usually  occurring  in  tangled  masses,  distinguished  from  the 
other  species  of  northern  range  by  the  combination  of  softer 
texture,  longer  cells,  and  light  color. 

7.  C.  CAUFORNICA  Collins,  P.  B.-A.,  No.  664  ;  1906,  p.  106. 
Filaments  attached  by  a  small  disk,  about  20  cm.  long,  straight 
or  flexuous,  of  uniform  diameter  throughout,  not  contracted  at 
the  nodes,  20-40 /u.  diam.,  cells  1-2  times  as  long  as  the  diam., 
rarely  3-4  times.     In  shallow  sandy  pools  near  high  water  mark, 
Southern  California. 


326  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

The  most  slender  erect  marine  species  known,  not  likely  to 
be  mistaken  for  any  other. 

8.  C.  CHELONUM  Collins,  1907,  p.  198.  Filaments  erect, 
straight,  12-20  /j.  diam.  at  the  base,  increasing  to  35  /x  diam. 
above;  lower  cell  up  to  50  diam.  long,  following  cells  5-10 
diam.,  upper  cells  2-3  diam.;  wall  thick;  attached  by  coralloid, 
pluricellular  branches  ;  fertile  upper  cells  moniliform  to  globu- 
lar, up  to  50  //.  diam.,  1-4  diam.  long.  Mich. 

The  only  fresh  water  Chaetomorpha  known  in  America,  and 
distinguished  from  all  other  species,  fresh  water  or  marine,  by 
the  pluricellular  branches  issuing  from  the  base  of  the  filament, 
which  may  form  a  dense,  inextricable  mass  on  the  substratum, 
which  in  the  original  and  so  far  only  known  station  was  the 
backs  of  living  turtles. 

Doubtful  species. 

C,  saccata  Kiitzing,  1849,  p.  380. 

C.  intestinalis  Kiitzing,  1849,  p.  380. 

C.  media  Kiitzing,  1849,  p.  380. 

C.  tenuissima  Crouan  in  Maze  and  Schramm,  1870-77,  p.  51. 
2.  RHIZOCLONIUM  Kiitzing,  1843,  p.  261. 

Filaments  usually  prostrate,  of  a  single  series  of  multinucle- 
ate  cells,  with  net-shaped  chromatophore  and  several  pyrenoids, 
uubranched  or  in  some  species  with  a  few  irregular  branches 
similar  to  the  axis,  and  with  more  or  less  numerous  rhizoidal 
branches,  mostly  unicellular,  but  sometimes  of  several  cells. 
Asexual  reproduction  by  biciliate  zoospores  with  stigma,  escap- 
ing through  an  opening  in  the  cell  wall ;  also  by  akinetes  ;  but 
in  only  a  few  species  has  either  form  of  fructification  been 
found. 

Common  plants  of  fresh  and  salt  water,  often  forming  exten- 
sive mats  in  shallow  water  or  on  ground  in  the  litoral  zone  ;  the 
filaments  resembling  those  of  Chaetomorpha,  but  less  uniformly 
cylindrical,  there  being  almost  always  more  or  less  irregularity 
in  the  form  of  the  cells.  The  short  rhizoidal  branches,  when 
present,  clearly  characterize  the  genus,  but  they  are  not  always 
developed,  and  when  they  are  absent,  the  resemblance  to  Chaeto- 
morpha is  deceptive.  In  the  few  species  where  there  are 
branches  other  than  rhizoidal,  they  are  formed  quite  differently 
from  those  of  Cladophora,  the  branch  pushing  the  original  fila- 
ment out  of  place,  itself  continuing  in  the  original  direction. 


THE  GREEX  AI.GAE  OF  NORTH  AMERTCX  327 

KEV   TO   THE   vS I'KC IKS    OK    RlU/.OCI.ON  H'M . 

I.     Marine.  2. 

i.     Fresh  water.  6. 

2.     Branches  at  least  in  part  similar  to  the  axis.  3. 

2.     Branches  when  present  short  and  rhi/.oidal.  4. 

3.     Forming  erect  tufts,  branching  only  at  the  base.        i.     R.erecium. 
3.  •  Branching  not  limited  to  base  of  tuft.  2.     R.  pachyderm u in. 

4.     Filaments  10-14  fj.  diam.;  branching  not  observed.  5. 

4.     Filaments  15-30  ^  diam.;  branches  few  or  many. 

3.     R.  ripariuni. 

4.     Filaments  40-70  /u  diain.  4.     R.  tortuosmn. 

5.     Cells  J-2  diam.  long.  5.     R.  Kochianum. 

5.     Cells  3-7  diam.  long.  6.     R.  A'enteri. 

6.     Branches  frequent,  pluricellular.  7. 

6.     Branches  wanting  or  unicellular.  8. 

7.     Filaments  12-22  /*.  9.     R.fontanum. 

7.     Filaments  50-90  ju.  10.     R,  Hookeri. 

8.     Cells  rarely  over  \%  diam.  long.  8.     R.crispmn. 

8.     Cells  2-8  diam.  long.  9. 

9.     Cell  wall  thin.  7.     R.  hieroglyphicum. 

9.     Cell  wall  thick,  6-13  M.  n.     •#•  crassipcllitum,  var.  robust  inn. 

1.  R.  ERECTUM  Collins,  igoia,  p.  291  ;    P.  B.-A.,  No.  975, 
Tufts  erect,  arising  from  prostrate  filaments  70-100 /u.  diam.,  of 
irregular-shaped,   very  thick-walled  cells,  1-2  diam.  long,  from 
which  arise  branches  either  simple  or  once  or  twice  forking  near 
the  base,  20-50  //.  diam.,  cells  3-6  diam.  long;  branches  up  to 
30  cm.  long,  but  so  much  and  so  regularly  crisped  that  the  tufts 
seldom  exceed   10  cm.  in  height.     In  tide  pools,  lower  literal, 
exposed  rocky  shore.     Me. 

Resembling  a  Cladophora  in  general  appearance,  but  with  the 
branching  limited  to  the  base  ;  intermediate  between  the  two 
genera,  but  apparently  nearer  to  Rhizocloninm. 

2.  R.  PACHYDERMUM  Kjellman,  1877,  p.  55,  figs.  26  and  28. 
Frond  at  first  attached,  main  axis  short,  85-100  p.  diam.,  with 
more  or  less  frequent  brano-hes,  50-75  /A  diam.,  cells  1-2  diam. 
long  ;  cell  wall  10-15  ^  thick,  lamellate  ;  main  axis  and  branches 
of  first  and  second  order  set  with  tapering  branches  of  few  cells, 
several  times  as  long  as  their  diam.,  with  thin  walls. 

Var.  TENUE  Kjellman,  1883,  p.  310.  Principal  branches  usu- 
ally 30-40  /u,  diam.;  cell  wall  usually  5-6  n  thick;  cauloid 
branches  more  numerous  than  in  the  type,  rhizoidal  branches 
fewer.  Greenland,  both  type  and  variety.  Northern  Kuropc. 

.3.     R.  RIPARIUM  (Roth)  Harvey,  1846-51,  PI.  CCXXXVIII ; 


328  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

1858,  p.  92  ;  Farlow,  1881,  p.  49.  Filaments  usually  pale  green, 
forming  expansions  on  ground  or  rocks  in  the  literal  zone  ;  cells 
usually  20-25  /j.  diatn.,  rarely  a  little  more  or  less,  length  one  or 
two  diameters. 

A  very  common  plant  on  both  Atlantic  and  Pacific  coasts, 
and  probably  in  arctic  and  temperate  regions  the'  world  over  ; 
occurs  also  inland,  near  salt  springs.  Three  varieties  are  to  be 
recognized ;  there  is  no  typical  form  distinct  from  these. 

Var.  IMPLEXUM  (Dillw.)  Rosenvinge,  1893,  p.  915,  fig.  34; 
P.  B.-A.,  Nos.  266,^976.  Forming  a  thin  fleece  on  mud  and 
sand  in  the  literal  zone ;  branches  few  or  none.  Greenland  to 
N.  J.,  Alaska  to  Wash.  Europe. 

Var.  POLYRHIZUM  (L,yng.)  Rosenvinge,  1893,  p.  915,  fig.  32  ; 
P.  B.-A.,  No.  24.  Sometimes  found  in  the  same  localities  as 
the  preceding  variety,  but  more  commonly  on  perpendicular 
cliffs,  where  it  hangs  in  skeins,  attaching  itself  to  the  rock  by 
numerous  branches  of  one  to  few  cells  each.  Greenland  to 
Conn.  ;  Cal.  J^urope. 

Var.  VALIDUM  (Gobi)  Foslie  in  Wittr.  and  Nordst.,  Alg. 
Kxsicc.,  No.  624.  Filaments  stouter  than  in  the  type,  30-50 /A 
diam.,  branches  frequently  unicellular,  often  continuous  with 
the  filament  cell.  Greenland.  Northern  Europe. 

Rhizoclonium  lanosum  Crouan  in  Maze  and  Schramm,  1870- 
77,  p.  53,  No.  1179,  and  Chaetomorpha  submaiina  Crouan,  I.e., 
p.  52,  No.  342,  from  authentic  specimens,  seem  to  belong  under 
R.  riparium  ;  Chaetomorpha  lanosa  Crouan,  I.e.,  p.  51,  No.  251, 
is  more  slender,  10-15  M  diam.,  and  seems  to  approach  R.  Kochi- 
anum  Kiitzing. 

4.  R.  TORTUOSUM  Kiitzing,  1845,  p.  206  ;  Farlow,  1881,  p. 
49  ;  P.  B.-A.,  No.  23  ;  Chaetomorpha  tortuosa  Harvey,  1858,  p. 
88,  PI.  XL/VI.B.  Filaments  dark  green,  40-70  p.  diam.,  cells 
1-2  diam.  long,  forming  curled  and  twisted  masses  in  tide  pools 
and  similar  localities.  Common  frojn  Gaspe  to  N.  Y.  ;  reported 
from  W.  I.  ;  Alaska  to  Washington.  Europe. 

Found  mostly  in  summer  on  exposed  shores,  where  the  dark 
green  crisped  masses  are  very  common  in  the  lower  pools  ;  it  is 
the  Chaetomorpha  tortuosa  of  Harvey,  1858,  but  hardly  the 
species  of  that  name  in  Hauck,  1885,  p.  443.  The  type  is 
without  branches. 

Forma  POLYRHIZUM  Holden,  P.  B.-A,  No.  625.  With  abun- 
dant rhizoidal  branches,  of  one  to  several  short  cells,  similar  to 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  329 

those  of  the  main  filaments,  the  terminal  cell  abruptly  conical. 
Me.,  Conn. 

5.  R.  KOCHIANUM  Kiitzing,  1845,  p.  206;  Vickers,  1908,  p. 
1 8,  PI.  XI  ;   L,e  Jolis,  Algues  marines  de  Cherbourg,  No.  236. 
Filaments  simple,  cells  12-14  /x  diam.,  1-2  diam.  long.     Form- 
ing masses  of  contorted  filaments  on  other  algae.     Barbados. 

Europe. 

6.  R.  KERNERI  Stockmayer,   1890,  p.  582;  P.   B.-A.,  No. 
623;    R.    Kochianum    Farlow,    1881,    p.    49.      Filaments   pale 
yellowish- green,  cells  10-14 /A  diam.,  3-7  diam.  long  ;  no  branch- 
ing.    Me.  to  Conn. 

This  species  and  the  preceding  are  of  about  the  same  diam- 
eter, differing  chiefly  in  the  length  of  the  cells.  R.  Kcrncri 
grows  in  masses,  loose  or  mixed  with  other  algae,  in  tide  pools 
or  below. 

7.  R.  HIEROGLYPHICUM  (Ag.)   Kiitzing,    1845,   p.  206;  P. 
B.-A.,  Nos.  718,  1192  ;  R.  lacustre  Kiitzing,  1849,  p.  385  ;    1853, 
PI.   LXXII,   fig.   4;    R.  antillarum  Kiitziug,    1849,   p.  384  ;  R. 
lacustre  forma  americannm  Wille,    1899,  p.   149  ;  "P.  B.-A.,   No. 
624;  R.  hicroglyphicum  var.   amciicanum   Wolle,    1887,   p.    144, 
PI.   CXXI,   figs.   31   and  32  ;    Rabenhorst,   Algen,    No.   2496. 
Filaments  not  much  curved  or  contorted,  10-25  p.  diam.,  2-5, 
rarely   1-7  diam.  long,  cel!s  sometimes  inflated  at  the  middle, 
and  of  larger  diam.  there  than  given  above ;  wall  not  over  2  ^ 
thick ;    branches  usually  absent,   when  present,   small,  tuber- 
cular or  rhizoidal,  rarely  partitioned  off  from  the  cell.    Fig.  119. 
Mass.,  Conn.,  Pa.,  111.,  Mo.,  Minn.,  Fla.,  W.  I.,  Cal. 

Europe,  Asia,  So.  America,  New  Zealand. 

A  very  common  and  variable  species,  including  the  greater 
part  of  the  fresh  water  forms. 

Var.  MACROMERE;S  Wittrock  in  Wittr.  and  Nordst.,  Alg. 
Exsicc.,  No.  630;  P.  B.-A.,  Nos.  119,  1191.  Cells  20-30  //. 
diam.,  5-12  diam.  long.  Mass.,  Conn.,  Cal.  Europe 

Var.  Hosfordii  (Wolle)  nov.  comb.;  R.  Hosfordii  Wolle, 
1887,  p.  145,  PI.  CXXII,  figs.  13-16;  P.  B.-A.,  No.  719.  Cells 
36-40  /u,  diam.,  3-6  diam.  long,  membrane  thick;  branches 
short,  rhizoidal.  Mass.,  N.  Y. 

Quite  different  from  the  ordinary  form  of  R.  hieroglyphicum, 
but  connected  by  var.  macromeres. 

8.  R.  CRISPUM  Kiitzing,  1845,  p.  206;   1853,  PI.  LXXI,  fig. 
i  ;   Filaments  12-22  p  diam.,  usually  much  crisped,  firm  ;  cells  i- 

rarely  2  diam.  long  ;  membrane  thick,  3-4^ ;  branches  infre- 
quent, unicellular  or  continuous  with  the  cell,  acute.  Me., 
N.  J.,  Md.  Europe. 


330  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Distinguished  from  R.  hieroglyphicum  by  the  thick  membrane, 
firmer  substance,  and  short  cells. 

9.  R.  FONTANUM  Kutzing,  1843,  p.  261  ;   1853,  PI.  LXXIV  ; 
R.fontinaleVJo\\z,  1887,  p.  144,   PI.  CXXI,  figs.  22-25.     Fila- 
ments 12-22  p.  diam.,  cells  2-4  diam.  long,  membrane  thickish  ; 
branches  usually  abundant,  mostly  pluricellular.     Me.,  Mass., 
Pa.,  111.,  Porto  Rico.  Europe. 

10.  R.  HOOKERI  Kiitzing,  1849,  p.  383;   1853,  PL  L,XVII, 
fig.  3 ;    Hohenacker,    Meeresalgen,   No.  477.     Filaments  stiff, 
usually  70  yu,  diam.,  sometimes  up  to  90  /u.;  cells  2-4  diam.  long, 
wall  thick,  4-10/4;  branches  sometimes  few,  sometimes  many; 
often  pluricellular,  occasionally  having  branches  of  a  second 
order.     W.  I.  So.  America,  Africa,  Asia. 

A  stout  species,  approaching  Cladophora  in  its  characters. 

11.  R.  CRASSIPELLITUM  var.  ROBUSTUM  G.  S.  West,  1905, 
p.  283.     Filaments  crisped,   occasionally  ventricosely  inflated, 
curved  and  genuflexed  ;    about  70  /u  diam.,  cells  1^-2  diam. 
long,  walls  very  thick  and  stratified,  up  to  I3/"-;  apical  cells 
somewhat  attenuate  and  rounded,  basal  cell  often  inflated  and 
producing  rhizoids ;    no  other  branching.      Forming  mats  on 
damp  earth.     W.  I. 

R.  crassipellitum  W.  and  G.  S.  West,  i897a,  p.  35,  with  fila- 
ments 33-43  p-  diam.,  wall  9-13  p.  thick,  is  found  in  W.  Africa.* 

*  W.  and  G.  S.  West,  1895,  p.  265,  PI.  XIV,  figs.  17-24,  describe  R.  Berg- 
grenianum  var.  dominicense ;  filaments  densely  intricate,  slender,  cells 
9-10  yu  diam.,  2-3  diam.  long,  wall  usually  thin,  a  large  proportion  of  the 
cells  with  short,  very  obtuse,  usually  unicellular  or  continuous  branches. 
In  hot  water  stream  in  crater  of  volcano,  Dominica.  The  typical  R. 
Berggrenianum  occurs  in  New  Zealand,  and  is  much  like  some  forms  of 
R.  hieroglyphicum,  but  has  akinetes  16-20  /j.  rtiam.,  1-3  diam.  long;  it 
may  be  merely  the  akinete- producing  form  of  J?.  hieroglyphicum.  West's 
plant  is  probably  an  abnormal  form,  due  to  the  hot  water,  etc. ;  as  it  has 
no  akinetes,  its  connection  with  R.  Berggrenianum  is  doubtful. 

G.  S.  West,  1905,  p.  283,  reports  from  Barbados  R.  hieroglyphicum 
var.  Kochianum  (Kiitz.)  Stockrnayer,  giving  the  dimensions  as  diam. 
23-29  n,  cells  i>£-2  diam.  long.  This  would  seem  to  agree  better  with  the 
type,  as  Stockrnayer  gives  12-13  /JL  for  the  diameter  of  var.  Kochianum. 

R.  occidental  Kutzing,  1853,  P-  22,  PI.  LXIX.  fig.  5,  from  Trinidad, 
seems  from  plate  and  description  to  be  hardly  distinguishable  from  R. 
hieroglyphicum.  R.  hieroglyphicum  var.  atrobrunneum  Tilden,  1898,  p. 
90,  PI.  VIII,  figs.  14-17,  from  Yellowstone  Park,  hardly  seems  to  have 
enough  distinctness  from  the  type  to  deserve  a  name.  Four  species  in 
Wolle,  1887,  must  be  considered  doubtful ;  R.  stagnate,  R.  fluitans,  R. 
Casparyi  and  R.  majus.  From  the  plate  CXXI,  figs.  26-28,  R.  fltt,itans 
might  be  considered  as  a  synonym  of  R.  crispum  Kiitz.  ;  but  a  specimen 
marked  R.fiuitans  by  Wolle  proves  to  be  Microspora  amoena  (Kiitz.) 
Rab.  If  R.  slagnale  is  the  same  as  R.  stagnorum  Wolle  n.  sp.,  Raben- 
horst  Algen,  No.  2577,  it  is  probably  a  coarse  short-celled  form  of  R. 
h  icroglyph  icu  m . 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  331 

3.     CLADOPHORA  Kiitzing,  1843,  p.  262. 

Frond  composed  of  filaments  of  a  single  series  of  cells,  the 
filaments  branching,  usually  abundantly ;  branching  lateral, 
but  often  coming  to  appear  dichotomous  in  conseqence  of  the 
pushing  aside  of  the  original  filament  by  the  branch  ;  growth 
chiefly  by  division  of  the  apical  cell,  subsequent  division  of  cells 
being  rather  exceptional  ;  branches  all  of  the  same  type  ;  cells 
multinucleate,  the  chromatophore  either  covering  the  cell  wall, 
or  forming  a  network  on  it,  or  in  the  form  of  numerous  small 
disks  ;  pyrenoids  several  in  a  cell ;  asexual  reproduction  by  4- 
ciliate  zoospores ;  sexual  reproduction  by  biciliate  gametes, 
uniting  and  germinating  immediately  ;  also  sometimes  germi- 
nating without  copulation. 

One  of  the  largest  genera  of  algae,  the  species  abounding  in 
fresh,  brackish  and  salt  water  the  world  over;  between  300  and 
400  species  have  been  described  ;  many  of  them  so  insufficiently 
that  they  can  hardly  ever  be  recognized.  There  are  few  sharply 
marked  characters  for  distinguishing  the  species,  it  being  mostly 
a  question  of  more  or  less  in  one  respect  or  another.  This  is 
specially  true  of  those  inhabiting  fresh  water,  of  which  an  al- 
most endless  list  of  species,  varieties  and  forms  have  been 
named,  many  duplicating  each  other,  many  founded  only  on 
temporary  stages  and  abnormal  conditions ;  a  careful  mono- 
graphing of  the  genus  would  be  a  most  valuable  contribution  to 
botany,  but  an  exceedingly  difficult  task.  In  the  meantime  we 
must  be  contented  with  recording  such  forms  as  seem  fairly  well 
marked,  leaving  it  for  the  future  to  determine  what  are  autono- 
mous species,  what  states  and  conditions. 

Some  species  of  Cladophora  appear  to  be  annual,  some,  per- 
haps the  larger  number,  are  perennial,  the  frond  dying  down 
almost  to  the  base,  which  persists  as  a  prostrate  matted  mass  of 
cells,  swollen  and  filled  with  reserve  material ;  when  new  growth 
begins,  the  filaments  issuing  from  the  older  cells,  which  cells 
may  perhaps  be  considered  as  akinetes,  are  so  distinct  in  char- 
acter that  if  occurring  separately  they  would  pass  for  quite  dis- 
tinct species.  Until  recently  there  have  been  included  under 
Cladophora  the  subgeuera  Acrosiphonia  (or  Spongomorphd)  and 
Acgagropila  ;  they  are  now  more  frequently  considered  as  sepa- 
rate genera  ;  while  by  some  writers  Acrosiphonia  and  Spongo- 


332  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

morpha  are  separated,  species  with  uninucleate  cells  being 
placed  in  the  latter,  those  with  multinucleate  cells  in  the 
former ;  both  being  distinguished  from  Cladophora  by  special- 
ized branches  of  a  different  type  from  the  original  normal  fila- 
ment. This  distinction  is  not  here  maintained,  all  species  with 
the  specialized  branches  being  included  under  Spongomorpha^ 
the  older  name  of  the  two.  No  such  distinction  is  possible  be- 
tween Cladophora  and  Aegagropila,  and  there  is  quite  a  possi- 
bility that  Aegagropila  forms  are  often  or  always  stages  or  con- 
ditions of  true  Cladophora  species.  Aegagropila  is  therefore 
not  here  maintained. 

It  has  not  seemed  practicable  to  arrange  the  species  in  sub- 
genera  or  sections ;  so  many  species  are  imperfectly  known 
that  any  arrangement  of  this  sort  would  be  untrustworthy  and 
misleading.  For  the  determination  of  a  specimen  the  key  will 
serve  as  well,  while  leaving  open  the  question  as  to  which  of 
the  characters  there  used  should  be  regarded  as  fundamental 
for  classification.  In  this  key  the  marine  and  fresh  water 
species  are  given  separately ;  an  arbitrary  division,  but  as  the 
key  is  only  for  the  purpose  of  determination,  and  does  not  at- 
tempt to  indicate  affinities,  this  plan  seems  justified.  The 
marine  species  are  first  given,  beginning  with  the  more  delicate 
erect  species,  then  the  larger  and  c  arser,  and  enditig  with 
prostrate  and  matted  forms ;  they  are  so  varied  that  it  is  impos- 
sible to  group  them  about  any  few  centers ;  by  bearing  in  mind 
that  everything  here  is  relative,  not  positive,  it  is  hoped  that 
the  key  will  be  of  use  to  students.  The  fresh  water  species 
follow,  falling  naturally  into  two  groups  ;  one  arranged  about  C. 
fracta,  the  other  about  C.  glomerata  ;  it  may  be  that  these'  two 
species  should  include  the  others,  but  for  the  present  it  is  more 
convenient  to  keep  them  separate. 

KEY  TO  THE  MARINE  SPECIES  OF  CLADOPHORA. 

i.     Plants  with  creeping,  matted  base.  2. 

i.     Plants  erect.  6. 

2.     Lower  part  of  filaments  300-350  /j.  diam.  41.     C.  intertexta. 

2.     Lower  part  of  filaments  less  than  300  ^  diam.  3. 

3.     Erect  branches  subsimple,  much  smaller  than  prostrate  filaments. 

38.     C.  Hozvei. 
3.     No  sharp  distinction  between  different  kinds  of  filaments.  4. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  333 

4.     Cells  cylindrical  throughout.  37.     C.  Magdalenae. 

4.     Some  cells  ovoid  or  pyriforin.  5. 

5.     Cells  40-70,  rarely  100  M  diani.  40.     C.  amphibia. 

5.     Cells  120-250  fj.  diatii.  39.     C.  trichotoma. 

6.     Main  filaments  from  150  M  up.  7. 

6.     Main  filaments  seldom  reaching  150  /u.  lo. 

7.     Lower  cells  10  diam.  long  or  more.  8. 

7.     Lower  cells  less  than  10  diam.  long.  n. 

8.     Di-  or  polychotomous  branching  normally  from  every  cell. 

34.     (7.  graminea. 

8.     Several  cells  usually  between  successive  branchings.  9. 

9.     Branching  alternate  or  opposite,  except  near  the  base. 

33.     C.  catenifera. 
9.     Branching  generally  dichotomous  throughout.     35.      (".  prolifera. 

10.     Cells  generally  with  a  sharp  constriction  near  the  base. 

12.     C.  constricta. 

10.     Cells  without  regular  constrictions.  20. 

ii.     Ramuli  curved.  25.     C.  microcladioides. 

ii.     Ramuli  straight  or  nearly  so.  12. 

12.     Ramuli  clustered.  13. 

12.     Ramuli  not  clustered.  14. 

13.     Ramuli  long,  slender,  cylindrical  or  nearly  so. 

26.     C.  fascicularis. 
13.     Ramuli  short,  stout,  with  constricted  nodes. 

28.     C.  Hut  chin  siae. 

14.     Diameter  nearly  the  same  in  all  parts  of  the  frond. 

36.     C.  fuliginosa. 

14.     Terminal  divisions  markedly  smaller  than  main  stems.  15. 

15.     Filaments  cylindrical.  2?.     C.  hirta. 

15.     Nodes  more  or  less  constricted.  16. 

16.     Cells  about  the  same  length  in  proportion  to  the  diameter  in  all 
parts  of  the  frond.  32.     C.  catenata. 

16.     Upper  cells  proportionally  shorter  than  the  lower.  17. 

17.     Ultimate  ramuli  very  short,  often  of  a  single  cell;    cells  in  ramuli 

ovoid,  1-2  diam.  long.  18.     C.  brachyclona. 

17.     Ultimate  ramuli  not  extremely  short.  18. 

j8.     Branching  patent,  except  at  the  extreme  base. 

15.     C.  crucigera. 

18.     Branching  generally  erect.  19. 

19.     Ramuli  not  exceeding  60  fj.  diani.  30.     C.  ovoidea. 

19.     Ramuli  70-100  M  diam.  •  31.     C.  utriculosa. 

20.     Main  filaments  distinctly  angled  or  flexuous.  21. 

20.     Main  filaments  straight  or  nearly  so.  34. 

21.     Ramuli  in  clusters  at  tips.  22. 

21.     Rainuli  not  distinctly  clustered.  23. 


334          TUFTS  COLLEGE;  STUDIES,  VOL.  II,  No.  3 

22.     Fronds  always  attached.  46. 

22.     Fronds  floating,  except  in  earliest  stages. 

16.     C.  cxpansa  i.  glomerata. 

23.     Fronds  floating,  except  in  earliest  stages.  24. 

23.     Fronds  always  attached.  28. 

24.     Ratnuli  in  long  pectinate  series  at  ends  of  filaments.  26. 

24.     Ramuli  scattered.  25. 

25.     Main  filaments  100-150  M  diam.  16.     C.  c.rpansa. 

25.     Main  filaments  30-60  M  diam.  27. 

26.     Filaments  40-100  M  diam. ;  cells  4-8  diam.  long. 

21.     C.  gracilis  v.  vadorum. 

26.     Filaments  up  to  160  /*  diam.  ;  cells  3-5  diam.  long. 

21.     C.  gracilis  v.  expansa. 

27.     Ramuli  straight ;  color  light.  n.     C.flavesccns. 

27.     Ramuli  curved  ;  color  dark.  13.     C.  crispula. 

28.     Frond  of  a  spongy  texture.  14.     C.flexuosa  f.  densa. 

28.     Frond  not  of  a  spongy  texture.  29. 

29.     Ramuli  short,  acute,  spine-like.  7.     C.  polyacantha. 

29.     Raniuli  not  spine-like.  30. 

30.     Articulations  long,  up  to  20  diam.  3.     C.  Rudolphiana. 

30.     Articulations  not  over  8  diam.  long.  31. 

31.     Ramuli  long,  in  pectinate  series  at  tips  of  branches.  32. 

31.     Ramuli  not  in  pectinate  series  at  tips  of  branches.  33. 

32.     Branching  patent ;  main  filaments  flexuous. 

21.     C.  gracilis  f.  anstralis. 

32.     Branching  erect ;  main  filaments  angular.  21.     C.  gracilis. 

32.     Branching  very  erect ;  fronds  up  to  i  meter  long. 

21.     C.  gra  cilis  f .  elo  nga  ta . 
33.     Fronds   light  or   pale   green  ;    plant  of   exposed   rocky  shores,  No. 

Atlantic  and  Pacific.  14.     C.flexuosa. 

33.     Frond  light  yellow-green  ;  little  known  So.  Atlantic  species. 

10.     C.  luteola. 

34.     Ramuli  curved.  35. 

34.     Ramuli  straight  or  nearly  so.  38. 

35.     Frond  of  a  spongy  texture.  i.     C.  albida  v.  refracta. 

35.     Frond  stiff  and  firm.  36. 

36.     Ramuli  closely  set  throughout.  37. 

36.     Ramuli  dense  at  tips  only.  17.     C.  scitula. 

37.     Main  branches  80  /x  diam.  or  more.  23.     C.  refracta. 

37.     Main  branches  not  over  50  n  diam.      24.    C.  Bertolonii  v.  hamosa. 

38.     Branches  opposite  or  whorled.  29.     C.  rnpestris. 

38.     Branches  not  opposite  or  whorled.  39. 

39.     Filaments  not  exceeding  30  n  diam.  j.     C.  albida. 

39.     Filaments  over  30  n  diam.  40. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA 


335 


40.     Ramuli  acute  ;  maiu  filaments  not  over  60  n  i 


40.     Ramuli  not  acute. 
41.     Main  branches  virgate. 
41.     Branching  chiefly  dichotomous. 
42.     Cells  of  ramuli  1-2  diam.  long. 
42.     Cells  of  ramuli  4  diam.  long  or  more. 
43.     Main  filaments  about  50  /u  diam. 
43.     Main  filaments  So  n  diam.  or  more.  6. 

44.     Ramuli  20-30  /u.  diam. 
44.     Ramuli  32-36  n  diam. 
45.     Branching  continuously  dichotomous,  except  as  to  ultimate  ramuli. 

9.     C.  Stiinpsoni. 
45.     Main   branching  dichotomous;    lesser  branches  and  ramuli  dense, 

largely  secund.  19.     C.  crystallina. 

Ultimate  ramuli  short,  stout.  27.     C.  laetevirens. 


lium. 

2.     C.  glancescens. 

41. 

42. 

45. 

43. 

44. 

4.  C.  dclicatula. 
C.  brachyclados. 

8.     C.  nitida. 

5.  C.virgatula. 


46. 

46.     intimate  ramuli  long,  slender. 


20.     C.  dalmatica, 


KEY  TO  THE  FRESH  WATER  SPECIES  OF  CLADOPHORA. 
i.     Fronds  floating,  except  in  the  early  stages.  2. 

I.     Fronds  permanently  attached.  7. 

2.     Forming  hard,  globular  masses.  52.     C.  holsatica. 

2.     Of  no  definite  form.  3. 

3.     Main  filaments  stout,  with  short  cells,  bearing  long,  slender,  secund 

ramuli.  50.     C.  secunda. 

3.     No  sharp  distinction  between  branches  of  different  orders.  4. 

4.     Main  filaments  bent,  cells  ovoid  or  pyriform,  branching  patent. 

47.     C.fracta. 

4.     Main  filaments  straight  or  nearly  so.  5. 

5.     Main  filaments  long,  with  few  branches.  51.     C.  insignis. 

5.     Main  filaments  freely  branching,  branches  with  many  ramuli.       6. 


6.     Ramuli  mostly  unicellular. 

6.     Ramuli  pluricellular,  long-celled. 
7.     Ramuli  in  dense  terminal  clusters. 
7.     Ramuli  not  in  dense  terminal  clusters. 

8.     Ramuli  recurved. 

8.     Ramuli  straight  or  slightly  incurved. 


48.     C.  oligoclona. 
49.     C.  crispata. 


43 


10. 

declinata. 
9. 


9.     Lower  branching  mostly  dichotomous  ;  branches  connate  for  some 

44-     C,  canalicularis. 


distance. 

9.     Branching  mostly  alternate  ;  branches  not  connate. 

42. 

10.     Not  over  i  cm.  high  ;  fil.  about  40  /x  diam.        53. 
10.     Larger,  10-40  cm.  high  ;  fil.  45  M  diam.  or  more. 
ii.     Main  filaments  75-125  M  diam.;  ramuli  35-50  M.     45* 
ii.     Main  filaments  45-85  v  diam  ;  ramuli  25-35^. 

46.     C.  Kuetzingiana. 


C.  glomerata. 

C.  uberrima. 

n. 

C.  callicoma. 


336          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

1.  C.    ALBIDA   (Huds.)    Kiitzing,    1843,    p.    267  ;     Harvey, 
1846-51,  PI.  CCLXXV;   1858,  p.  80;  Farlow,   1881,  p.  51;   P. 
B.-A.,    No.    1227.     Fronds    soft,    dense,   pale  green,   filaments 
20-30  /J.  diara.,  cells  4-5  diam.  long,  delicate  ;  branching  irregu- 
lar,   ramuli    long,    patent,    blunt.     Southern    New    England, 
Southern  Cal.  Europe. 

The  soft,  spongy  consistency  and  very  slender  filaments  suf- 
ficiently distinguish  the  growing  plant,  and  generally  the  dried 
specimen. 

Var.  REFRACTA  (Wyatt)  Thuret  in  Lejolis,  1863,  p.  60;  P. 
B.-A.,  No.  720;  C.  refract*  Harvey,  1846-51,  PI.  XXIV;  1858, 
p.  79.  Upper  branches  and  ramuli  recurved;  otherwise  like 
the  type.  New  Jersey  to  Maine.  Etirope. 

In  habit  quite  different  from  the  type,  but  not  in  dimensions, 
etc.  It  seems  to  be  commoner  than  the  type,  and  to  extend 
farther  north  on  this  coast.  It  shades  into  the  type,  and  older 
specimens  are  liable  to  be  mistaken  for  slender  forms  of  C.  flexuosa; 
in  the  growing  plant  the  texture  is  sufficient  for  distinction,  ex- 
cept from  C.  flexuosa  forma  densa  ;  in  this  case  the  dimensions 
of  cells  must  be  depended  on,  as  also  in  distinguishing  from 
forms  of.C.  refracta. 

2.  C.  GLAUCESCENS  (Griff.)  Harvey,    1846-51,  PI.  CXCVI ; 
1858,  p.  77;   Farlow,    1881,  p.  52;   P.  B.-A.,  No.  817.     Fronds 
10-40   cm.  long,    glaucous   or   yellowish-green,    loosely  tufted, 
much  branched,  ending  in  long,  erect,  acute,  alternate  or  some- 
times  secund   ramuli;  cells   at   base  50-60  /u  diam.,  in  ramuli 
25-30 /u. ;    cells  usually  4-6  diam.  long,  sometimes  considerably 
longer.     Florida  to  Labrador.  Europe. 

A  plant  of  the  litoral  zone,  and  in  the  northern  part  of  its 
range,  a  plant  of  spring  and  early  summer.  It  is  common  in 
warm  upper  pools,  exposed  to  the  full  sunshine,  the  upper  part 
of  the  tuft  fading  almost  to  white.  It  grows  also  in  marsh  pools 
and  shallow  bays,  where  the  water  is  warm. 

3.  C.  RUDOLPHIANA  (Ag.)  Harvey,  1846-51,  PI.  LXXXVI ; 
1858,  p.  80;   Farlow,    1881,  p.  54;   P.  B.-A.,  No.   267.     Fronds 
loose,  soft,  yellowish-green,  gelatinous,  up  to  a  meter  in  length  ; 
main  filaments  40-60  p.  diam.,  branches  alternate  or  opposite, 
patent,   flexuous,   ramuli  secund,   tapering,   about  20  p.  diam., 
cells  always  much  longer  than  broad,  sometimes  up  to  20  diam. 
long.     Kennebunk,  Maine  to  New  Jersey,  and  probably  farther 
south.  Europe. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  337 

A  plant  of  the  upper  sublitoral  zone,  growing  in  warm,  shal- 
low bays,  often  in  large  quantities.  Apart  from  the  microscopic 
characters,  to  which  recourse  must  be  had  in  mounted  speci- 
mens, the  growing  plants  can  generally  be  distinguished  from 
the  nearest  species,  C.  albida  and  C.  gracilis,  by  the  consistency 
of  the  frond.  C.  albida  is  soft  and  spongy  ;  C.  Rudolphiana  soft 
but  not  spongy  ;  C.  gracilis,  even  in  its  most  slender  forms,  has 
a  certain  harshness  to  the  touch. 

4.  C.  DEUCATULA   Montague,  1850,  p.  302  ;    Kiitzing,  1856, 
PI.  I,  fig.   2.     lyoosely  tufted,  soft,  dull  green,  about  10  cm. 
high  ;  filaments  40-60  yu,  diam.  below,  4-6   diam.  long  ;    loosely 
branching,    branches   virgate,   erect ;    ramuli   in   short   secund 
series,  seldom  over  8  cells  in  length,  cells  20-30  /*  diam.,  1-2 
diam.   long ;    joints  somewhat   constricted.     Florida,   Jamaica, 
Porto  Rico,  Cal.  South  America. 

A  delicate  plant  varying  in  the  amount  of  ramification,  and 
especially  as  to  the  frequency  of  the  ramuli. 

5.  C.    VIRGATULA  Grunow,    1867,  p.  38.     Fronds  7-10  cm. 
high,  soft,  pale  green,  virgate,  with  subsimple  main  stem,  beset 
with    long,    erecto-patent,    subsecund    branches,    issuing    from 
almost    every    joint ;    connate    for   a   short    distance.     Ramuli 
simple   or  with  a  few  subsecund  ramelli ;    cells  of   main  axis 
75-110  fj.  diam.,  3-6  diam.  long;  of  the  ramuli  45-55  .p-  diam., 
3-4  diam.  long;  of  the  ramelli  32-36  /*  diam.,  2-3  diam.  long; 
terminal  cells  subtorulose.     Guadeloupe. 

The  above  is  copied  from  Grunow's  description  ;  the  plant 
resembles  C.  delicatula,  but  is  larger. 

6.  C.  BRACHYCLADOS  Montague,  18383,  p.  15,  PI.  IV,  fig.  2  ; 
Harvey,  1858,  p.  81.     Filaments  erect,  80-100  p.  diam.,  primary 
branches  long,  patent,  with  numerous  appressed  ramuli ;    ulti- 
mate ramuli  very  numerous,  very  short,  secundly  pectinate,  ^o- 
40  fj.  dram.;    cells  in  main  filaments  5  diam.  long,  in  ramuli   2 
diam.;   nodes  contracted.     Cuba. 

Resembling  C.  delicatula,  but  a  larger  plant,  not  so  delicate, 
with  joints  more  uniformly  constricted  ;  C.  virgatula  also  seems 
near  it,  but  according  to  the  description  the  latter  has  more 
abundant  main  branches  and  fewer  ramuli. 

7.  C.   POLYACANTHA  Montague,   1850,  p.  302  ;   C.  flexuosa 
forma  Floridana  Collins,  P.  B.-A.,  No.  978.     Tufts  dull  green, 
10-20  cm.  high;    filaments  dichotomous  below,  50-80  /u,  diam.; 
branches  long,  rather  stiff,  flexuous,  usually  with  naked  apex, 
elsewhere  set  with  long  similar  branches,  30-50  /u  diam.,  and 


338  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

with  numerous  short,  acute,  spine-like  ramuli,  25-35  /"•  diam.,  of 
two  or  three  cells  each.  On  rocks  exposed  to  the  waves, 
Florida.  -So.  America, 

Somewhat  resembling  C.  delicatula,  but  stiffer,  branches  less 
ereqt,  and  usually  more  abundant ;  ramuli  more  acute,  and  not 
so  distinctly  secund. 

8.  C.  NITIDA  Kiitzing,  1843,  p.  269;   C.  trichocoma  Kiitzing, 
1854,  PI-  XXIX, fig.  2  ;    Collins,  1901,  p.  244.     Fronds  yellow- 
ish or  whitish  green,  soft,  dense,  somewhat  mucilaginous,  usu- 
ally up  to  10  cm.  high,  occasionally  much  more  ;  main  filaments 
50-100  /JL  diam.,  bearing  more  or  less  frequent  straight,  virgate 
branches,    with    alternate    or    secund,    rarely    opposite,     erect 
branches  of  higher  orders,  and  secund  slender  ramuli,  20-30  p. 
diam.;  cells  cylindrical,    from  4-12  diam.  long,  usually  over  6 
diam.     Jamaica,  Bahama.  Europe. 

The  fronds  of  this  species  are  soft  and  slippery,  often  forming 
long,  skein-like  masses,  similar  to  some  species  of  Rhizoclonium. 
In  the  American  specimens  identified  with  this  species,  the  fila- 
ments are  more  slender  than  in  most  European  forms.  In  the 
north  of  Europe  it  seems  to  be  stouter  and  harsher  than  with  us  ; 
but  some  Mediterranean  forms  are  soft  and  nearty  as  slender 
as  the  plants  from  Jamaica. 

9.  C.  STIMPSONI    Harvey,    iSsga,    p.    333;    P.  B.-A.,    No. 
729.     Fronds  loosely  tufted,  up  to  30  cm.  high,  light  green,  of 
delicate  and  silky  texture  ;  filaments  100-150  /x  at  base,  tapering 
gradually  upward,  di-  trichotomously  divided,  branches  contin- 
uously   but   distantly    forking,    successively   smaller,    ultimate 
branches  lateral,  secundly  pectinate  with  long  ramuli,  20-25  P- 
diam.,  with  rounded  or  slightly  pointed  tips.     Cells  5-8  diam. 
long,  longest  near  the  base.     On  shells,  etc.     Southern  Califor- 
nia,. Japan. 

A  soft,  delicate,  silky  plant,  reminding  one  of  the  more 
slender  forms  of  C.  gracilis,  but  distinct  in  manner  of  branching, 
substance  and  cell  dimensions. 

10.  C.  LUTEOLA  Harvey,  1858,  p.  81.     Fronds  pale  yellow- 
green,  tufted,  very  slender,   much  branched,  not  matted ;    very 
flexuous,  with  rounded  angles  ;  branching  irregular,  frequently 
trichotomous ;    ramuli    secund    or   opposite,    at    the    tip    pecti- 
nate,   somewhat    corymbose   and    crowded ;    cells    cylindrical, 
about  60  /u,  diam.  in   main  branches,  35  p.  in  ramuli,  6-8  diam. 
long.     Key  West,  Fla.,  Cuba. 

11.  C.  PLAVESCENS  (Roth)  Kiitzing,  1843,  P-  267;  Harvey, 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  339 

1846-51,  PI.  CCXCVIII;  C.  fracta  forma  Jiavescens  Collins, 
1902,  p.  124;  P.  B.-A.,  Nos.  1077,  1229.  Filaments  at  first 
attached,  later  loose  floating,  30-60  /A  diam.,  forking  at  wide 
angles,  cells  6-10  diam.  long;  ramuli  not  much  smaller,  taper- 
ing but  with  blunt  tips  ;  forming  dense  yellovrish-green  floating 
masses  in  high,  warm  pools.  Mass,  to  N.  Y.  I^urope. 

This  form  occurs  in  high  rock  pools,  where  the  water  is  quite 
salt ;  it  has  generally  been  considered  a  form  of  C.  fracta,  but 
is  a  smaller  plant,  attached  in  early  stages,  and  inhabits  strictly 
salt  water. 

12.  C.  CONSTRICTA  Collins,  1909,  p.  19,  PI.  IvXXVIII,  figs. 
4  and  5.    Tufts  dense,  up  10  cm.  high,  somewhat  fastigiate  ;  main 
filaments  up  to  65  ^  diam.,  branches  smaller,  ultimate  ramuli 
about    25   fj.   diam.;    cells  5-20   diam.    long,    mostly  somewhat 
clavate,  often  with  a  distinct  annular  constriction  about   one 
diameter  above  the  lower  end.     Branching  mostly  opposite  be- 
low and  often  above,  but  also  often  lateral,  the  short  ramuli  some- 
what secund  ;  branches  at  first  rather  patent  but  soon  curving 
upward  ;  apex  of  terminal  cell  shortly  conical  with  rounded  tip. 

In  general  appearance  not  unlike  a  small  and  dense  form  of 
C\  £/-acilis  such  as  is  often  seen  in  shallow  pools  on  the  north  At- 
lantic coast,  but  the  resemblance  is  merely  external,  the  branch- 
ing being  more  like  that  of  C.  rupestris.  The  cells  vary  much 
in  length,  but  average  quite  long  and  usually  increase  slightly 
in  diameter  from  base  to  summit.  In  the  older  parts  the 
branching  is  quite  regularly  opposite  or  apparently  trichoto- 
mous.  The  branching  is  quite  dense,  the  outline  usually  reg- 
ular. The  constriction  does  not  occur  on  all  the  cells,  but  is 
often  very  distinct,  the  diameter  of  the  cell  being  reduced  at  this 
point  to  less  than  half  the  normal,  the  interior  thickening  of  the 
cell  walls  contributing  to  this  reduction  ;  a  slight  manifestation 
of  a  character  that  is  quite  important  in  some  Valoniaceae. 

13.  C.   CRISPULA  Vickers,    1905,   p.   56  ;    1908,   p.    19,    PI. 
XVI.     Forming   dark    green    spongy  masses  of  contorted  fila- 
ments,   45-50   p.   diam.,   twisted   in   rope-like   tufts;     branches 
alternate  or  opposite,  near  the  tips  somewhat  secund,  curved  ; 
cells  about  8  diam.  long.     Barbados. 

Resembling  in  habit  a  Chaetomorpha ,  but  with  genuine 
branching. 

14.  C.  FLEXUOSA   (Griff.)  Harvey,  1846-51,   PI.   CCCLIII; 
1858,  p.  78;  Farlow,   1881,  p.  54;  P.  B.-A.,  Nos.    1076,   1527. 


340          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Fronds  10-20  cm.  high,  light  green;  main  filaments  80-120  /u. 
diam.,  regular!}'  flexuous,  with  flexuous  alternate  branches, 
40-80  p.  diam.,  with  alternate  or  secund,  curved  and  sometimes 
refracted  raniuli ;  cells  from  6  diam.  long  below  to  2  in  the 
ramuli.  Newfoundland  to  Bermuda  and  Florida,  Alaska. 

Europe. 

A  plant  of  nearly  the  same  range  on  the  Atlantic  as  C.  glau- 
cescens ;  it  will  probably  be  found  on  the  Pacific  to  the  south  of 
Alaska.  It  occurs  in  rock  pools,  but  usually  near  low  water 
mark,  and  generally  in  colder  places  than  C.  glaucescens. 
It  is  a  firmer  plant,  larger  in  all  dimensions  except  total  length  of 
frond,  and  is  distinctly  flexuous  throughout.  On  the  other 
hand  the  larger  forms  of  this  species  approach  small  forms  of  C. 
gracilis,  C.  hirta,  and  C.  laetcvirens^  and  it  is  often  difficult  to 
draw  the  line.  Typical  C.  gracilis  has  long  secund  ramuli  pec- 
tinately  arranged  at  the  end  of  every  branch ;  C.  hirta  has 
rather  shorter  ramuli  in  secund  series  all  along  the  filaments; 
C.  laetcvirens  has  short,  stout  ramuli  in  dense  fascicles  at  the 
tip.  By  these  characters  normal  forms  can  be  distinguished 
without  much  difficulty.  C.flcxuosa  Vickers,  1908,  p.  19,  PI. 
XV,  is  hardly  our  plant ;  the  figure  is  rather  like  a  slender 
form  of  C.  gracilis. 

Forma  DENSA  Collins,  1902,  p.  121  ;  P.  B.-A.,  No.  979. 
Branching  of  all  orders  very  dense  ;  texture  of  frond  spongy. 
At  lower  limit  of  literal  zone.  Newport,  R.  I. 

Habit  like  C.  albida,  but  form  and  dimensions  of  cells  like  C. 
flexuosa. 

15.  C.    CRUCIGERA   Grunow,    1867,    p.    38.     Fronds   stout, 
pale    green,  rather   loose,   sparingly    dichotomously  branched  ; 
branches   patent,   connate   for   a    short   distance   at   the   base ; 
ramuli  scattered,  short,  of  few  cells,  alternate  or  oftener  oppo- 
site, very  patent ;  cells  about  300  /u.  diam.  below,  6-8  diam.  long  ; 
ramuli  75-110  p.,   3-4  diam.  long,  somewhat  constricted  at  the 
nodes.     Guadeloupe. 

Grunow's  description  has  been  copied  ;  he  considers  this  a 
very  distinct  species,  not  to  be  mistaken  for  anything  else. 

16.  C.  EXPANSA  (Mert.)  Ktitzing,  1853,  PI.  XCIX  ;  Farlow, 
1881,  p.  55;  P.  B.-A.,  Nos.  121,  977,  1280.     Fronds  dull  green, 
loosely  branched,   main   branches   100-150  p  diam.,   flexuous, 
with  smaller,  patent,  secondary  branches,  divaricately  divided  ; 


THE  GREKN  ALGAE  OF  NORTH  AMERICA          341 

ramuli  40  ^  diam.,  secund,  blunt;    cells  3-6  diam.  long.     In 
warm  pools  and  lagoons.     Newfoundland  to  New  Jersey. 

Europe. 

Common  in  summer  in  marsh  pools  and  lagoons  where  the 
temperature  is  high  and  the  level  varies  little  ;  at  first  attached, 
it  soon  rises  to  the  surface,  and  ultimately  forms  a  dense  felty 
coating,  continuous  over  large  stretches  of  water,  usually  mixed 
with  Lvn^ln'ii  ncstiiarii  and  species  of  Itnteromorpha.  It  will 
probably  be  found  to  extend  in  both  directions  beyond  the 
limits  given.  Reports  of  C.fracta  from  marine  stations  prob- 
ably should  be  referred  to  this  species. 

Var.  GI.OMERATA -Thuret  in  Le  Jolis,  1863,  p.  61  ;  P.  B.-A., 
No.  1027.  Ramuli  in  closely  set  tufts.  Long  Island  Sound. 

Ei 'trope. 

The  tufted  ramuli  give  quite  a  distinct  appearance  ;  otherwise 
it  is  like  the  type. 

17.  0.   SCITULA  (Suhr)   Kiitzing,    1849,    p.   399;    1854,    PI. 
XII,  fig.  i  ;   Conferva  scitula  Suhr,   1831,  p.  685  ;    1834,   PI.  II, 
fig.  2.     Frond  small,   brownish-green,   stiff,   densely  fascicled ; 
filaments  erect,  branching,  branches  erect,  connate  at  the  base, 
above  recurved,  with  short,  secuud  ramuli ;  lower  cells  75-110  /* 
diam.,  2-4  diam.  long.     W.  I. 

The  figure  by  Suhr  shows  a  small,  perhaps  immature  plant 
with  a  few  simple,  slightly  recurved  branches  and  many  short, 
secund  ramuli  ;  the  figure  by  Kiitzing,  apparently  from  an  older 
plant,  shows  rather  virgate  main  axes,  densely  set  with  some- 
what secund  branches  ;  the  ramuli  at  the  ends  of  the  branches 
arranged  much  as  in  Ectocarpns  fascicnlatus.  The  cells  in  the 
main  axes  are  about  3  diam.  long;  in  the  ramuli  1-2  diam. 
long  ;  the  tips  are  blunt  and  rounded.  The  description  above 
is  from  Kiitzing,  and  there  is  possibly  a  doubt  as  to  the  identity 
with  Suhr's  plant;  if  they  are  not  the  same,  Kiitzing's  had 
better  stand  for  the  species,  as  Suhr's  figures  and  descriptions 
are  hardly  sufficient.  There  is  no  recent  record  of  it. 

1 8.  C.  BRACHYCLONA  Montagne  in  Kiitzing,   1849,  p.  394  ; 
1853,  PI.   XCVI,  fig.  2.     Fronds  loosely  tufted,  pale  green  or 
yellowish,    10-15  cm.   high;  filaments  di-  polychbtomous,    150- 
250 /u,  diam.,  in  main  divisions;    branches  at  first  distant,  then 
more  abundant  ;  ramuli  very  short,  often  of  a  single  cell,  alter- 
nate, opposite  or  secund,  50-75  n  diam.;  cells  of  main  divisions 


342     TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

cylindrical,  4-6  diam.  long ;  shorter  in  the  branches,  with  con- 
stricted joints;  in  the  ramuli  ellipsoid,  1-2  diam.  long.  Ber- 
muda. Mcditerra  n  ea  n . 
No  authentic  specimens  have  been  accessible,  but  the  Ber- 
muda plant  agrees  so  well  with  Kiitzing's  figure  that  the  iden- 
tity seems  fairly  well  assured. 

19.  C.  CRYSTALLINA  (Roth)  Kiitzing,    1845,   p.    213;   1854, 
PL    XIX,   fig.    2.     Fronds    yellowish   or   whitish-green,    soft, 
glossy,  10-30  cm.  high  ;  filaments  slightly  matted,  distantly  di- 
trichotomously  branched;  main  branches  80-140  p-  diam.,  taper- 
ing to  25-40  /A  in  the  ramuli ;  branching  erect  or  patent ;  upper 
ramuli  sometimes  whorled  or  alternately  secund  ;  cells  cylindri- 
cal, 4-12  diain.  long.     Mass.,  W.  I.  Europe. 

A  quite  variable  plant,  but  usually  marked  by  its  light  color 
and  silky  gloss,  which  latter  has  given  the  specific  names  crys- 
tallina,  sericca  and  nitidissima  to  various  forms.  The  long 
cells,  often  as  long  in  the  ramuli  as  in  the  main  filaments,  are 
also  characteristic.  The  plant  distributed  under  this  name  as 
P.  B.-A.,  No.  723,  is  probably  not  correctly  determined.  C. 
sericca  Vickers,  1908,  p.  18,  PI.  XIV,  may  be  a  shorter  jointed 
and  divaricately  branched  form  of  this  species,  but  has  also  con- 
siderable resemblance  to  the  following. 

20.  C.  DALMATICA  Kiitzing,    1343,   p.   268;   Vickers,    1908, 
p.  19,  PI.  XIV.B.     Fronds  up  to  5  cm.  high,  light  green  ;   main 
filaments  80-120  /n  diam.,  simple  or  distantly  dichotomous  below, 
trichotomous  above,  with  many  alternate  or  secund  branches  ; 
cells  3-6  diam.   long ;     ultimate   ramuli   corymbose,    incurved, 
secund,  30-50  p.  diam.;  cells  1^-3  diam.  long,  nodes  contracted, 
membrane  thickish.     Barbados.  f-'.uropc. 

21.  C.  GRACILIS  (Griff.)   Kiitzing,    1845,   p.   215;    Harvey, 
1846-51,  PL  XVIII;   1858,  p. 80;   Farlow,  1881,  p.  55  ;   P.  B.-A., 
Nos.  1528,  1529,  not  No.  724.     Fronds  usually  not  over  30  cm. 
long,    yellowish   or   glaucous   green,    somewhat   harsh    to   the 
touch;    main    filaments    up    to   160  yu,  diam.,  irregularly  bent, 
branching  at  the  angles ;  the  branches  more  slender,  set  at  the 
tips  with  secund  series  of  long,  attenuate,  acute  ramuli,  40-60  /u, 
diam.  ;   cells   3-5  diam.   long   throughout.     Greenland   to  Key 
West.  Europe. 

A  variable  species,  passing  into  C.  lactcvirens,  C.  hirta,  and 
C.  flexuosa ;  see  under  the  last  for  special  distinctions.  It 
assumes  various  forms  under  different  environment  and  at  dif- 
ferent stages  of  growth,  and  until  one  is  familiar  with  it,  will 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  343 

often  be  very  puzzling.  The  angular  main  stem  and  the  pecti- 
nate terminal  ramuli  are  the  only  constant  marks  to  distinguish 
it  from  other  species  of  the  same  general  dimensions.  It  seems 
to  be  common  from  Massachusetts  to  Nova  Scotia,  both  on  ex- 
posed shores  and  in  bays  ;  more  than  most  species  of  Cladophora 
it  thrives  in  places  where  it  is  quite  out  of  water  at  low  tide. 
Several  forms  occurring  on  the  New  England  coast  have  re- 
ceived names. 

Yar.  VADORUM  (Aresch.)  Collins,  1902,  p.  122;  C.grncilh 
var.  tennis  Farlow,  lo&i,  p.  55  ;  C.  vadorum  Wittr.  and  Nordst., 
Alg.  Exsicc.,  Nos.  1045,  1046.  Filaments  more  slender  than 
in  the  type,  40-100  /x,  cells  4-8  diam.  long.  Forming  loose, 
floating  masses  in  the  sublitoral  zone,  N.  S.  to  N.  J.  Europe. 

Forma  ELONGATA  Collins,  1902,  p.  122;  P.  B.-A.,  No.  725. 
Frond  stretching  out  on  the  surface  of  shallow  water  to  a  length 
of  a  meter  or  more ;  very  glaucous  green  ;  branches  distant  and 
very  erect.  In  shallow  warm  pools  where  there  is  a  definite 
stead}'  current ;  coast  of  Maine. 

Forma  EXPANSA  Farlow,  1881,  p.  55,  as  variety;  P.  B.-A., 
No.  981.  Frond  soon  detached,  forming  loose  floating  masses, 
irregularly  branched.  Tide  pools,  coast  of  Maine  and  Massa- 
chusetts. Forming  floating  masses,  similar  to  C.  cxpausa,  but 
not  so  dense. 

Forma  SUBFLEXUOSA  Collins,  P.  B.-A.,  No.  1530.  Fronds 
shorter  than  in  the  type,  branching  dense,  branches  flexuous. 
A  somewhat  reduced  form  of  shallow  rock  pools  in  northern 
New  England. 

This  form  appears  to  originate  in  pools  where  the  water  is 
shallow,  and  there  is  no  current ;  where  the  water  is  shallow 
and  a  current  runs  through  when  the  tide  is  out,  forma  clongata 
is  produced. 

Forma  australis  n.  f.  Filaments  less  sharply  angular; 
branches  of  all  orders  more  patent.  The  common  form  south 
of  Cape  Cod  ;  the  opposite  extreme  from  forma  elongata,  but 
connected  by  every  gradation. 

22.  C.  HIRTA  Kiitzing,  1845,  p.  208;  1854,  PI.  I,  fig.  2  ;  P. 
B.-A.,  No.  726.  Fronds  20-30  cm.  high,  stiff  and  harsh;  fila- 
ments 150-200  fj.  diam.  at  base,  dull  green,  much  or  little 
branched  ;  all  set  throughout  or  frequently  with  short,  subacute, 
more  or  less  secund  ramuli ;  cells  2-4  diam.  long,  rarely  some- 
what more.  In  rather  exposed  places,  Greenland  to  Long 
Island  Sound,  and  probably  extending  farther  south.  Europe. 


344          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

In  dimensions  and  general  form  somewhat  like  coarse  C. 
gradlis  of  the  northern  type,  but  distinguished  by  ramuli  gen- 
erally distributed  over  the  filaments,  not  merely  at  the  tips. 
The  amount  of  ramification  varies  much  ;  the  most  characteris- 
tic forms  have  long,  little  branched  filaments  set  with  longer 
or  shorter  secund  series  of  ramuli ;  the  much  branched  forms 
are  less  characteristic,  and  require  more  careful  examination. 

23.  C.  REFRACTA  (Roth)  Areschoug,   Alg.   Exsicc.  Scand., 
No.   338;    Farlow,    1881,   p.    52;    P.  B.-A.,   No.   573.     Fronds 
tufted,  glaucous  or  dull  green,  10-20  cm.  high  ;  filaments  rather 
stiff,  100-120  /u.  diam.   below,   40-50  /u,  in  the   ramuli;  cells  2-3 
diam.  long  ;  branches  of  all  orders  at  first  erect,  then  reflexed ; 
ramuli  often  secund,  blunt.     N.  S.  to  N.  J.  Europe. 

The  regularly  reflexed  branches  of  all  orders  distinguish  this 
from  all  our  other  species  of  the  same  range  except  some  forms 
of  C.  ftexuosa  and  C.  albida  var.  refracta  ;  the  former  is  a  more 
open  plant,  with  flexuous  rather  than  refracted  branches  ;  the 
latter  has  more  slender  filaments  and  softer  substance.  C.  re- 
fracta has  a  characteristic  habit,  hard  to  describe,  but  fairly  rec- 
ognizable when  once  seen.  For  C.  refracta  Harvey,  see  C. 
albida  var.  refracta. 

24.  C.  BERTOLONII  var.  HAMOSA  (Kiitz.)  Ardissone,  1886, 
p.  242  ;   C.  hamosa  Kiitz.,  1854,  PI.  VIII,  fig.  2.     Tufts  3-iocm. 
high,  dark  green;  filaments  rather  stiff,  80-100  p.  diam.  in  the 
main   divisions,  25-30  p.  in  the  ramuli ;  much  branched,   main 
divisions  di-trichotomous,  set  with  alternate,  opposite  or  whorled 
branches,  usually  short,  and  with  densely  set,  secund,  recurved 
ramuli;     cells    1^-3  diam.    long,  rarely  more;    terminal  cells 
rounded,  not  tapering.     Cal.  Mediterranean. 

The  California  plant  seems  to  be  more  slender  than  the 
European,  seldom  exceeding  60  /j.  in  the  main  branches  and 
25  p.  in  the  ramuli.  The  dark  color,  short  cylindrical  cells  and 
elegant  feathery  tips,  with  a  long  series  of  secund,  usually 
slightly  recurved  ramuli  on  the  similarly  recurved  branch,  are 
fairly  clear  characters. 

25.  C.  MICROCLADIOIDES  Collins,  1909,  p.  17,  PI.  LXXVIII, 
figs.  2  and  3.    Fronds  more  or  less  densely  tufted,  10-20  cm.  high  ; 
filaments  about  200  /A  diam.  at  base,  cells  4-6  diam.  long  ;  stiff, 
straight  or  flexuous,  distantly  di-trichotomous,  branches  simi- 
lar, erect  or  more  or  less  recurved,  bearing  on  the  upper  (inner) 
side  numerous  short  branches,  rarely  with  very  short  branches 


THE  GREEN  ALGAE  OK  NORTH  AMERICA  345 

opposite  one  or  more  of  them  ;  this  ramification  continued,  the 
ultimate  ramuli  of  very  few  cells,  80-100  /u.  diam.,  cells  i}4-2}4 
cliam.  long.  Cal. 

A  stout  but  graceful  species,  with  a  characteristic  ramifica- 
tion like  that  of  Microcladia  borcalis  Ruprecht.  There  is  consid- 
erable variation,  according  as  the  main  divisions  are  straight  or 
flexuous,  the  branches  close  or  distant,  erect  or  recurved  ;  but 
the  peculiar  symmetrical  ramification  will  distinguish  it  from 
any  other  of  our  species.  As  many  as  four  cells  may  sometimes 
be  found  issuing  from  the  much  widened  top  of  a  cell,  all  flabel- 
lately  arranged  in  one  plane. 

26.  C.    FASCICULARIS   (Mert.)    Kiitzing,    1843,    p.   268;    P. 
B.-A.,   Nos.   122,    1228,    1472;  Vickers,  1908,  p.  18,  PI.  XIII ; 
Conferva    fascicularis  Montagne,    1839,   p.  4,    PI.   VII,   fig.    i. 
Fronds  elongate,  up  to  50  cm.  long  ;  main  filaments  and  princi- 
pal branches  flexuous,  sparingly  alternately  branched,  the  ends 
beset  with  rather  long,  pectinate,  more  or  less  densely  fascicu- 
late ramuli;    main  filaments  200-250  p.  diam.,  cells  2-4  diam. 
long;    ramuli    80-120   p.  diam.,   cells   usually    1-2    diam.   long. 
Florida,  W.  I.  So.  America. 

A  common  and  quite  variable  species,  something  of  the  range 
of  variation  "being  shown  by  the  specimens  distributed  in 
P.  B.-A. 

27.  C.  LAETEVIRENS  (Dillw.)  Harvey,    1846-51,   PI.   CXC ; 
1858,  p.  82  ;   Farlow,    1881,-  p.   53  ;    Conferva  glomerala  Wyatt, 
Alg.  Danm.,  No.  143.     Filaments  50-150  /u,  diam.,  rigid,  yellow- 
green,  much  branched  ;  branches  erect,  often  opposite  ;  ultimate 
ramuli  short,  obtuse  or  subacute,  densely  fastigiate  at  the  tips 
of  the  branches ;    fronds   up    to    20  cm.   long ;     cells    in    main 
branches  6  diam.  long,  in  ramuli  3  diam. 

A  stout  and  rather  coarse  species,  best  characterized  by  the 
dense  tufts  at  the  ends  of  the  branches,  formed  of  stout,  blunt 
ramuli ;  it  grows  at  the  lower  limit  of  the  literal  or  in  the  sub- 
litoral  zone,  and  is  not  a  common  species.  The  reports  of  this 
species  from  the  west  coast  are  all  doubtful.  Me.,  Mass. 

28.  C.  HUTCHINSIAE  (Dillw.)  Kiitzing,   1845,  p.  210;  Har- 
vey, 1846-51,  PI.  CXXIV  ;   Farlow,  1881,  p.  53.     Fronds  glau- 
cous green,  up  to  40  cm.  high  ;  filaments  120-300  /*  diam.,  stiff, 
flexuous,  sparingly  branched  ;  ramuli  few,  secund,  blunt,  with 
constricted  nodes;  cells  2-3  diam.  long-.     Florida  and  W.  I.  to 
New  Jersey  ;   Vancouver  Island.  Europe. 


346          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

The  largest  species  of  the  North  Atlantic  coast,  not  to  be  mis- 
taken for  any  other  species  occurring  there.  It  has  been  re- 
ported from  few  localities,  but  is  likely  to  be  found  at  various 
points  south  of  Cape  Cod,  and  on  the  west  coast  south  of 
Vancouver. 

Var.  DISTANS  (Ag.)  Kiitzing,  1849,  p.  392  ;  C.  diffusa  Harvey, 
1846-51,  PI.  CXXX;  1858,  p.  83;  Conferva  diffusa  Wyatt, 
Alg.  Damn.,  No.  144.  Main  branches  long,  nearly  bare  of  sec- 
ondary branches  ;  cells  longer  than  in  the  type ;  nodes  not  con- 
stricted. Mass,  to  New  Jersey.  Europe. 

Connected  with  the  type  by  intermediate  forms. 

29.  C.  RUPESTRIS    (Iv.)    Kiitzing,    1843,    p.    270;     Harvey, 
1846-51,    PI.    CIvXXX ;     1858,    p.    74;    Farlow,    iSSi,    p.    51; 
P.  B.-A.,    No.  728.     Fronds  densely  tufted,    dark  green;  fila- 
ments stiff,  150  p.  diam.  at  the  base,  70-80  /x  in  the  ramuli ;  cells 
3-4  diam.  long ;  branches  opposite  or  in  whorls  of  four,  erect  ; 
ramuli   short,    blunt   or   subulate.     Greenland  to    Gay    Head, 
Mass.  Eitrope. 

A  distinct  species,  growing  usually  on  rocks  in  the  litoral 
zone,  especially  in  places  covered  by  Fuel  and  other  large 
algae  ;  when  growing  it  is  a  rich  dark  green,  but  in  drying  the 
color  becomes  duller  and  the  plant  seems  coarse  ;  it  seems  to  be 
in  as  good  condition  in  winter  as  in  summer,  while  most  North- 
ern species  of  Cladophora  are  spring  and  summer  plants. 

30.  C.   OVOIDEA  Kiitzing,    1843;  p.   266;   1853,    PI.   XCII, 
fig.  i.     Fronds  5-15  cm.  high,  stiff,  rather  dull  green  ;  filaments 
distantly  dichotomous,  150-200  /A  diam.  below,  branches  becom- 
ing more  lateral  and  secund  above  ;  upper  ramuli  not  over  60  /JL 
diam  ,  tips  rounded  or   slightly  pointed;    cells  in   lower  part 
cylindrical,  4-8    diam.   long;    above   ovoid,    1^-3    diam.   long. 
Santa  Cruz,  Cal.  and  vicinity.  Europe. 

This  plant  is  often  found  in  collections  bearing  the  name  of  C. 
cartilaginea  ;  but  that  species  is  probably  a  Spongomorpha. 

31.  C.  UTRICULOSA  Kiitzing,  1843,  p.  269;   1853,  PL  XCIV, 
fig.  i  ;    Wittr.   and   Nordst.,   Alg.    Exsicc.,    No.   929.     Fronds 
tufted,  light  or  dull  green,  10-20  cm.  high;  filaments  firm,  sub- 
membranaceous,  di-  potychotomous,  100-250  ft  diam.  near  base, 
in  upper  part  set  with  lateral,  often  secund  ramuli,    70-100/01 
diam.  ;  cells  6-8  diam.  long  below,  2-4  diam.  above.     Jamaica, 
Bahama,  Porto  Rico.,  etc.  Europe,  So.  America. 

A  species  varying  much  in  size,  extent  of  branching,  etc. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  347 

32.  C.  CATENATA  (Ag.)  Ardissone  in  Rabenhorst,  Algen, 
No.  1293.     Fronds  densely  tufted,  dark  green,  stiff,  up  to  8  cm. 
high;  filaments  much  branched,   di-  trichotomous  below,  200- 
250 /u.  diam.  ;  80-150  p.  in  ratnuli ;  cells  3-6  diam.  long,  nodes 
constricted ;    ramuli    opposite,    secund    or   irregularly    placed, 
somewhat  fasciculate;  terminal  cell  usually  obovoid.     Jamaica. 

Europe. 

Found  throughout  the  Mediterranean,  but  so  far  reported  at 
only  this  one  locality  in  America.  Somewhat  like  a  more 
delicate'  C.  prolifera. 

33.  C.    CATENIFERA    Kiitzing,     1849,    p.    390;     1853,     PI. 
LXXXIII,    fig.    i.     Fronds   stiff,  cartilaginous   or    horn-like, 
flexuous,  more  or  less  densely  branched,   up  to  50  cm.  high  ; 
main  filaments  300-500  p.  diam.  at  base,  alternately  or  sometimes 
oppositely  branched,   branches  patent,   the  last  series  bearing 
opposite  or  alternate,  more  or  less  densely  fasciculate  ramuli, 
100-225  p.  diam.;  cells  in  main  stem  long,  up  to  20  diam.,  cylin- 
drical ;   in  branches  8-10  diam.,  slightly  constricted  at  nodes; 
in  ramuli  1^-2  diam.,  oblong.     Jamaica,  Bermuda. 

Cape  of  Good  Hope. 

A  noble  plant  in  its  larger  forms,  resembling  mostly  C.  pellu- 
cida,  under  which  name  it  has  sometimes  been  reported.  That 
species,  however,  is  quite  regularly  di-  polychotoinous,  branch- 
ing at  the  top  of  each  cell.  C.  catenifera  varies  much  as  to  its 
rigidity  or  softness,  and  as  to  the  density  of  the  fascicles  of 
ramuli ;  but  the  other  characters  seem  to  be  quite  permanent. 

34.  C.  GRAMINEA  Collins,  1909,  p.  19,  PI.  LXXVIII,  fig.  6. 
Loosely  tufted,  10-15  cm-  high,  dark   green,  cartilaginous,  dis- 
tantly   di-   trichotomous,    all   divisions   erect ;    main    filaments 
about   300  p.  diam.,  ultimate  divisions  about    150^  diam.,  tips 
blunt  or  slightly  acute  ;  cells  very  long  below,  up  to  30  diam., 
shorter  above  ;  normally  occupying  the  space  from  one  forking 
to  another  ;  ultimate  branches  4-6  diam.  long;  cell  walls  usually 
strongly  striate.     Cal. 

Distinguished  from  all  our  other  species  by  the  long  cells,  each 
normally  extending  from  one  forking  to  the  next ;  in  this  it 
agrees  with  C.  pcllucida  (Huds.)  Kiitz.  of  Europe,  but  in  the 
latter  there  is  more  reduction  of  size  in  the  successive  orders  of 
branches,  the  main  filament  being  sometimes  as  large  as  500  p. 
diam.,  while  the  ultimate  ramuli  are  seldom  over  50  p.,  and  are 
dense  and  more  or  less  fasciculate.  In  C.graminea  there  is 


348          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

comparatively  little  diminution  in  size,  and  the  tips  are  loose 
and  open.  In  C.  pelhidda  the  divisions  of  the  di-  or  trichotomy 
are  usually  equal  and  develop  equally ;  in  C.  graminea  one  is 
often  much  reduced,  sometimes  only  a  single  cell. 

35.  C.  PROLIFERA  (Roth)  Kiitzing,  1845,  p.  207;   1853,  PI. 
LXXXII,   fig.  3  ;  Vickers,    1908,   p.    18,    PI.  XII  ;  Wittr.  and 
Nordst.,   Alg.   Exsicc.,   No.    1043.     Fronds  dense,  dark  green 
when  growing,  blackish  when  dried,  up  to  20  cm.  high,  rarely 
more ;    filaments    coarsely    membranaceous    or    cartilaginous, 
300-400  I*,  diam.,  di-trichotomous,  divisions  mostly  erect,  more 
frequent  towards  the  somewhat  fastigiate  tips  ;  ramuli  130-200 
/A  diam.,  blunt;  cells  up  to  20  diam.  in  main  filaments,  much 
shorter  in  the  branches,  4-6  diam.  long  in  the  ramuli.     In  lower 
literal  zone  and  in  shallow  water,  Porto  Rico,  Barbados. 

Europe. 

A  coarse,  dark  colored,  rather  unsightly  plant,  common  in  the 
Mediterranean,  and  generally  in  the  warmer  Atlantic. 

36.  C.  FULIGINOSA  Kiitzing,  1849,  p.  415.     Forming  large, 
dark  brownish-green  tufts  ;  filaments  hard,  stiff,  more  or  less 
densely  matted,  150-160  //,  diam.;  cells  cylindrical,  5-10  diam. 
long  ;  the  main  axes  long,  set  with  short,  blunt  ramuli,  often 
in  secund  series.     Florida,  W.  I. 

This  species  was  described  from  Cuban  specimens,  and  has 
apparently,  never  been  since  reported.  The  writer  is  indebted 
to  Dr.  Bornet  for  calling  his  attention  to  the  fact  that  it  is  ap- 
parently the  same  as  the  Cladophora  that,  in  combination  with 
an  endophytic  fungus,  Blodgettia  Borneti  Wright,  1881,  p.  21, 
PI.  II,  figs.  1-4,  makes  up  the  Blodgettia  confervoides  Harvey, 
1858,  p.  48,  PL  XL,V.C,  and  which  was  distributed  under  the 
last  name  as  P.  B.-A.,  No.  314.  The  hyphae  of  the  fungus  may 
possibly  occur  in  connection  with  some  other  species  of  Clado- 
phora, but  in  all  specimens  observed  the  host  agrees  fairly 
well  with  the  description  of  C.  fuliginosa. 

37.  C.    MA.GDALENAE    Harvey,    1846-51,    PI.    CCCIyV.A; 
Farlow,  1881,  p.  56;  P.  B.-A.,  No.  572.     Fronds  short,  coarse, 
dull  green,  60-100  p.  diam.,  matted,  procumbent,  with  patent, 
flexuous   branches,    bearing  a  few  irregularly  placed,    curved 
ramuli;  cells  2-4  diam.  long.     R.  I.  and  Conn.  Europe. 

A  coarse,  unsightly  plant,  creeping  in  tangled  masses  among 
other  algae  in  the  literal  zone,  in  late  autumn  and  winter.  Not 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  349 

a  well  understood  species,  and  perhaps  it  may  some  time  prove 
to  be  a  winter  form  of  something  else. 

38.  C.  HOWEI  Collins,    1909,  p.    18,    PI.   LXXVIII,  fig.  i. 
Forming  dense  matted  tufts,  consisting  of  creeping  basal  fila- 
ments, with  irregular  cells  about    150  //,  diam.,  tapering  to  75  ^ 
at  the  growing  tips,  cells  1-3  diam.  long;  from  these  basal  fila- 
ments arise  vertical  filaments  about  50  p.  diam.  at  base,  tapering 
to  20-25  p.  at  the  rounded  or  slightly  pointed  tip  ;  cells  about 
5-6  diam.  long  at  the  base,  up  to  15-20  diam.  long  near  the  tip  ; 
sparingly  branched,  branches  erect  or  appressed,  similar  to  the 
erect  filaments.     Bermuda. 

Forming  a  dense  coating  in  tide  pools,  about  i  cm.  high  ;  the 
base  a  mat  of  dark  green,  much  branched,  irregular  fila- 
ments, from  which  arise  the  slender,  slightly  branched,  long- 
jointed  filaments,  pale  green  under  the  microscope,  yellow  in 
the  mass.  This  yellow  color  may  not  be  a  permanent  charac- 
ter, as  the  same  shade  appears  to  be  produced  by  local  condi- 
tions in  some  algae  normally  green.  The  contorted,  densely 
matted  basal  filaments  indicate  an  affinity  to  the  sub-genus 
Aegagropila,  but  there  is  no  indication  of  a  definite  form  to  the 
whole  mass. 

39.  C.  TRICHOTOMA  (Ag.)   Kiitzing,   1849,  p.  414;   1854,  PI. 
LXIV,  fig.    i;   P.   B.-A.,   No.   820;   C.   repens,   P.   B.-A.,   No. 
727,  not  of  Harv.;   C.  columbiana  Collins  in  Setchell  and  Gardner, 
1903,  p.  226.     Forming  light  or  bright  green,  densely  pulvinate 
masses,  2-5  cm.  high ;    filaments  procumbent  at  base,  stiff,  di- 
trichotomous  with  rather  few  short,  alternate,   rarely  opposite 
branches,  fastigiate  at  the  tips;  cells  120-250/11  diam.,  4-10  diam. 
long,   nearly  cylindrical  below,   above  ovoid  to  pyriform  ;    the 
branches  about  the  same  diameter  as  the  filament.     Vancouver 
Island  to  Southern  Cal.  Europe. 

In  habit  like  C.  repcns,  but  of  lighter  or  brighter  color  and 
larger  cells.  It  grows  in  rock  pools  near  high  water  mark,  and 
has  been  found  from  Vancouver  to  the  Mexican  boundary.  It 
seems  impossible  to  draw  any  sharp  line  between  C.  trichotoma 
and  C.  columbiana  ;  the  form  distributed  as  C.  repens,  P.  B.-A., 
No.  727,  differs  so  much  from  the  Mediterranean  plant  that  it 
seems  best  to  include  it  under  the  present  species. 

40.  C.  AMPHIBIA  Collins,  1907,  p.  200;  P.  B.-A.,  No.  1284. 
Basal  layer  of  densely  branching  prostrate  filaments,  cells  cylin- 
drical, 40-70  /A  diam.  and  2-5  diam.  long,  or  fusiform,  1-2  diam. 


350          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

long,  swollen  to  100  //.  in  the  middle  ;  emitting  erect  filaments, 
cells  30-50  //,  diam.,  4-8  diam.  long,  cylindrical  or  irregular, 
terminal  cell  obtuse  or  truncate  ;  slender  descending  rhizoids 
sometimes  issuing  from  lower  cells  of  erect  filaments.  Cal. 

A  dull  green,  unattractive  plant,  growing  near  extreme  high 
water  mark,  among  Salicornia,  in  a  salt  marsh,  and  having  much 
the  habit  of  Vaucheria. 

41.  C.  INTERTEXTA  Collins,    1901,   p.    243;    P.  B.-A.,   No. 
8 1 8.     Tufts    densely    matted,    prostrate ;    filaments    300-350   /x 
diam.,  creeping  over  shells  and  sand;  cells   1-1^2  diam.  long, 
rarely  up  to  3   diam.;  bearing  upright  branches,    about  200  //, 
diam.,  simple  or  with  a  few  short,  secund  ramuli  ;  terminal  cells 
blunt.     Jamaica. 

Forming  dense,  tangled  masses  in  the  bottom  of  pools  ;  the 
naked  branches  projecting,  giving  the  whole  the  appearance  of 
a  tangled  mass  of  Chaetomorpha. 

42.  C.  GLOMERATA  (Iy.)    Kiitzing,    1845,  p.  212;   P.  B.-A., 
No.    1283.     Fronds  up  to  30  cm.   high,    more  or  less  densely 
branched  below,  branches  more  and  more  frequent  towards  the 
top,  at  last  forming  dense  fascicles ;  filaments  cylindrical,   75- 
100  ju,  diam.  below,  6-7  diam.  long  ;  35-50  /A  diam.  in  the  ramuli, 
3-6  diam.   long ;    ramuli  not  tapering,  tips  rounded  ;    fruiting 
cells  terminal  or  subterminal.      Fig.  124. 

An  extremely  variable  species  and  not  marked  by  any  dis- 
tinct lines  from  the  four  following  species.  Specimens  distrib- 
uted in  P.  B.-A.,  No.  1283,  correspond  fairly  with  the  typical 
form  ;  the  plant  distributed  as  C.  glomerata,  P.  B.-A.,  No.  473, 
belongs  rather  in  forma  rivularis ;  No.  278,  Tilden,  American 
Algae,  is  a  quite  elongate  form ;  a  plant  from  the  Mississippi 
River,  Winona,  Minn.,  comes  nearer  to  the  type  than  to  any  of 
the  following  varieties,  and  Tilden,  American  Algae,  No.  35,  C. 
callicoma,  probably  belongs  here.  Wolle  gives  few  definite 
localities ;  some  specimens  marked  by  him  C.  glomcrata  have 
been  examined,  but  they  are  very  imperfect  and  uncharacter- 
istic. No.  32,  Tilden,  American  Algae,  is  distributed  as  C. 
glomerata  var.  fasciculata  Rab.  ;  the  only  character  distin- 
guishing this  from  the  type  is  found  in  the  swollen  terminal 
cells  ;  but  as  this  appears  to  be  due  to  the  formation  of  spores, 
and  is  probably  the  same  throughout  the  species,  the  varietal 
name  seems  unnecessary.  Var.  clavata  Wolle,  1887,  p.  128,  ap- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  351 

pears  also  to  be  merely  a  fruiting  state  of  some  L 'ladophora  ;  the 
specimen  distributed  under  this  name  in  Tilden,  American 
Algae,  No.  34,  was  sterile  in  the  copy  examined,  and  charac- 
terless. 

Forma  RIVULARIS  Rabenhorst,  1868,  p.  341  ;  P.  B.-A.,  No. 
473 ;  Tilden,  Amer.  Algae,  No.  33.  Frond  elongate,  more 
open,  fascicles  of  ramuli  rather  distant.  Housatonic  River, 
Conn.  ;  San  L,eandro,  Cal. 

Forma  MUCOSA  Kiit/ing,  1849,  p.  406;  Tilden,  Amer.  Algae, 
No.  537.  Soft  and  mucilaginous  ;  color  deep  green.  Niagara 
Falls,  Lake  Ontario,  Charlotte,  N.  Y. ;  Minn. 

43.  C.  DECUNATA  Kiitzing,  1849,  p.  406  ;   1854,  PI.  XXXV. 
Fronds    usually    loosely    branched,    with   lateral    and   terminal 
glomerules  of  recurved  ramuli ;    cells  of  main  branches  cylin- 
drical,   80-100  p.  diam.,    3-10   diam.    long;    of   ramuli   50-60  p. 
diam.,  swollen  and  often  variously  distorted.     California. 

Europe. 

In  habit  somewhat  resembling  the  marine  C.  refrada.  The 
California!!  specimens  have  long,  subsimple  branches  with  quite 
long  cells,  and  set  at  intervals  with  tufts  of  curved  and  more  or 
less  distorted  ramuli.  C.  glomcrata  var.  parvula  Bailey  in  Rab- 
enhorst, Algen,  No.  520;  Wolle,  1887,  p.  128,  is  made  a  form 
of  this  species  by  Rabenhorst,  1868,  p.  340.  A  specimen  dis- 
tributed under  this  name  in  Tilden,  American  Algae,  No.  37, 
hardly  shows  the  characters  of  this  species.  No.  38  of  the 
same  distribution,  C.  declinata  \&r.fluitans  (Kg.)  Hansg.,  1886, 
p.  84,  does  not  have  the  characters  indicated  by  Hansgirg. 

44.  C.  CANAUCUI.ARIS  (Roth)  Kut/.ing,  1845,  p.  214;   1854, 
PI.  XLIII,  fig.  i  ;•  Wolle,  1887,  p.  126.     Fronds  5-10  cm.  high, 
much  branched,  branching  mostly  di-  trichotomous,  branches 
connate  at  the  base  ;  ramuli  often  fasciculate ;  main  filaments 
85-120  p.  diam.,  cells  5-8  diam.  long;  cells  in  branches  shorter, 
in  ramuli  1-1%  diam.  long,  35-50/1.  diam.,  somewhat  swollen  ; 
cell  membrane  usually  thick. 

While  no  definite  localities  can  be  given,  it  is  probable  that 
this  species  occurs  with  us  ;  it  seems  to  be  little  more  than  a 
rather  coarse  C.  glomcrata.  The  occurrence  of  connate 
branches  is  not  uncommon  in  various  species  of  Cladophora, 
both  fresh  water  and  marine,  and  the  length  of  the  cells  is  a 
very  uncertain  character.  Wolle's  figures,  Pi.  CXI,  figs,  i  and 


352          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

2,  are  not  clear  enough  to  justify  his  determinations  ;  No.  143, 
Tilden,  American  Algae,  does  not  show  the  characters  of  the 
species.  This  143  is  given  as  C.  canalicularis  (Roth)  Kg.  var. 
gcnuina  Rabenh.,  1868,  p.  342  ;  no  such  combination  appears 
on  that  page,  or  apparently  elsewhere  in  the  work. 

45.  C.    CALLICOMA     Kiitzing,     1843,    p.    267 ;     1854,    PL 
XXXVII,  fig.    i;     Rabenhorst,    Algen,    No.    2166.     Forming 
rather  dense,  soft  tufts,  up  to  30  cm.  high  ;  filaments  75-125  /u, 
diam.  below,  35-50  p.  in  the  ramuli ;  cells  cylindrical  or  slightly 
inflated  below,  distinctly  inflated  in  the  ramuli,  6-8  diam.  long 
below,  2-4  in  the  ramuli ;  branching  subdichotonious  below,  then 
alternate,  and  in  the  ramuli  alternate  or  somewhat  secund  ;  tips 
rounded.     Housatonic  River,   Conn. ;  Long  Brook,  Princeton, 
N.  J.  ;   Montana. 

Forming  soft  tufts  in  streams  ;  usually  quite  dense,  but  the 
tips  penicillate  rather  than  glomerate.  An  authentic  specimen, 
received  by  the  kindness  of  Dr.  Bornet,  shows  dimensions 
larger  than  those  usually  given ;  the  specimens  distributed 
under  this  name  as  Nos.  25  and  919  P.  B.-A.,  seem  to  be  rather 
C.  Kuetzingiana  Grunow.  A  plant  from  Watkins'  Glen,  N.  Y., 
agrees  well  with  this  species;  Wolle  records  C.fluitans  from 
this  locality,  but  the  specimen  just  mentioned  is  evidently  not 
that  species. 

46.  C.    KUETZINGIANA   Grunow   in    Rabenhorst,    1868,  p. 
342  ;   C.  callicoma  P.  B.-A.,  Nos.  25,  919.     Forming  soft,  rather 
loose  and  feathery  tufts  up  to  30  cm.  high  ;  filaments  45-85  fi 
diam.  below,   ramuli  25-35  /*  diam.  ;   cells  cylindrical  or  in  the 
ramuli  slightly  swollen;    6-10  diam.  long  below,  occasionally 
longer ;   2-4  diam.  long  in  the  ramuli ;  branching  erect,  opposite 
or  alternate  below,  but  the  ramuli  generally  secund,  rather  long 
and  tapering,  with  acute  or  subacute  tips.     Still  River,  Conn.  ; 
Lake  Washington,  Seattle,  Wash. 

A  large  but  delicate  species,  with  long,  feathery  tufts  ;  grow- 
ing in  lakes  and  rivers.  It  appears  to  be  the  C.  macrogonya  of 
Kiitzing,  but  not  of  Rabenhorst,  Algen,  No.  2384,  nor  the 
Conferva  glomerata  var.  macrogonya  of  Lyngbye,  1819,  PL  LI II. 

The  following  forms  seem  to  belong  under  C.  Kuetzingiana,  as 
here  understood  :  • — 

C.  glomerata  var.  callicoma  forma  B or cali- Americana  Brand  in 
Tilden,  American  Algae,  No.  536.  Primary  filaments  gener- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  353 

ally  connate  at  the  base  ;  filaments  63-70  p.  diam.  below,  ramuli 
20 //. ;  cells  8-15  diam.  long.     Minn. 

C.  glomcrata  var.  callicoma  forma  Minnesotana  Brand  in 
Tilden,  American  Algae,  No.  538;  P.  B.-A.,  No.  1379. 
Glomerules  not  conspicuous,  branches  seldom  connate ;  fila- 
ments 70-80/1  diam.,  ramuli  17  /x ;  cells  5-8  diam.  long.-  Minn., 
California. 

47.  C.  FRACTA  (Dillw.)  Kiitzing,  1843,  p.  263;   1854,  PI.  I,.  ; 
Wolle,    1887,    p.  124;    P.  B.-A.,    Nos.    120,    816,    1281,    1282. 
Fronds  forming  loose,  floating  masses,  usually  of  a  dark  green 
color  ;  branching  irregular,  filaments  much  bent   and  curved  ; 
main  filaments  60-120  p.  diam.,  cells  1-3  diam.  long  ;  ramuli  20- 
40  p.  diam.,  cells   3-6   diam.   long;     cells    seldom    cylindrical, 
mostly  ovoid,  clavate  or  irregular  ;  fruiting  cells  never  terminal. 

A  species  of  world-wide  distribution,  taking  on  innumerable 
shapes  which  have  received  names  as  forms,  varieties  and 
species  ;  one  of  these  is  retained  here  as  a  species  in  the  same 
way  as  four  are  retained  in  connection  with  C.  glomcrata,  but 
with  much  doubt  as  to  their  representing  distinct  specific  types. 

Forma  GOSSYPINA  (Kiitz.)  Rabenhorst,  1868,  p.  335  ;  Algen, 
No.  2576;  Wolle,  1887,  p.  125  ;  Tilden,  American  Algae,  No. 
141.  Filaments  slender,  sparingly  branched;  forming  dense, 
interwoven,  silky  masses.  Pa.,  Idaho.  Europe. 

Form  SUBSIMPLEX  Kiitzing,  1845,  p.  218.  Filaments  very 
slightly  branched  ;  easily  mistaken  for  a  Rhizodonium .  Mass. 

Europe. 

Forma  RIGIDULA  (Kiitz.)  Rabenhorst,  1868,  p.  335.  Fila- 
ments stout  and  stiff,  loosely  branched.  Conn.  Europe. 

Forma  REFLEXA  Collins,  P.  B.-A.,  No.  1194.  Main  branches 
stout,  flexuous ;  branches  of  higher  orders  patent  or  reflexed, 
often  in  secund  series.  Cal. 

Forma  STREPENS  (Ag.)  Rabenhorst,  1868,  p.  335  ;  C.  strepens 
Kiitzing,  1854,  PI.  XLVIII,  fig.  2  ;  C.  fracta  var.  calcarea  Til- 
den, American  Algae,  No.  142.  Branching  irregular;  main 
filaments  90-125  /x.  diam.;  ramuli  25-40  p. ;  cells  cylindrical  or 
swollen,  varying  in  length  from  i  to  6  diam.  in  the  same  fila- 
ment ;  the  whole  plant  more  or  less  incrusted  with  lime.  So. 
Dakota.  ,  So.  Europe. 

48.  C.  OLIGOCLONA  Kiitzing,  1845,  p.  218;   1854,  PI.  UV. 
Filaments  sparingly  branched,  pale  or  dirty  green  ;  main  fila- 
ments mostly  dichotomous,  secondary  filaments  elongate,  beset 
with    short,    mostly  unicellular  ramuli ;    cells    cylindrical    to 


354          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

slightly  clavate,  in  the  main  branches  2-6  diam.  long,  45-55  M 
diam.;  in  the  ramuli  4-10  diam.  long,  30-40  ^  diam.  Europe. 
Both  the  type  of  this  species  and  the  var.  Flotowiana  are  given 
by  Wolle,  1887,  p.  126,  as  occurring  "in  stagnant  water"  and 
it  is  quite  probable  that  this  species  occurs  here,  though  no  cer- 
tain specimens  have  been  seen.  Tilden,  American  Algae,  No. 
29,  in  the  specimen  examined  is  quite  insufficient  and  unde- 
terminable. The  label  gives  the  diam.  of  the  main  cells  as  75  n, 
of  the  branches  as  43  p. ;  considerably  above  the  figures  given  by 
Wolle  or  Kirchner.  No.  30  of  the  same  distribution  is  labelled 
C.  oligoclona  Kg.  var.  flotowiana  (Kg.)  Hansg.  Prodr.  81,  and 
the  filaments  are  stated  to  be  15  //.  diam.;  an  examination  of  the 
specimen  shows  that  they  are  really  60  /JL  diam.  in  the  main 
branches.  Hansgirg  gives  dimensions  for  the  same  40-56  p.. 
The  confusion  is  such  that  no  conclusion  can  be  drawn  from 
Miss  Tilden's  specimens  or  Wolle's  descriptions  and  figures. 

49.  C.  CRISPATA  (Roth)  Kiitzing,  1843,  p.  264;  Wolle, 
1887,  p.  126.  Forming  loose  masses;  main  filaments  sparingly 
branched  laterally  or  dichotomously  ;  branching  above  alternate, 
more  dense,  and  filaments  more  slender  in  each  order  of 
branches  ;  main  filaments  40-75  p.  diam.,  in  some  varieties  some- 
what more;  in  ramuli  20-35  P,  cells  cylindrical,  5-20  diam. 
long,  usually  proportionally  longer  in  the  ramuli  than  in  the 
main  filaments ;  ramuli  not  tapering,  rounded  at  the  end  ;  cell 
wall  thin  and  delicate. 

The  very  long,  slender  filaments  with  erect  branches  gradu- 
ally decreasing  in  size,  with  long,  delicate  cells,  make  this  a 
fairly  distinct  species.  Many  varieties  have  been  described, 
but  they  are  rather  vague  in  their  distinctions. 

Forma  VITREA  (Kiitz.)  Rabenhorst,  1868,  p.  336;  Algen,  No. 
1529  ;  Kiitzing,  1854,  PI.  XL,  fig.  i.  A  delicate  pale  form,  with 
long  cells ;  Iowa.  The  plant  distributed  under  this  name  in 
Tilden,  American  Algae,  No.  277,  seems  to  be  rather  C.  Kuetz- 
ingiana  Rab. 

As  No.  2570,  Rabenhorst,  Algen,  is  distributed  under  the 
name  of  C.  crispata  Roth  h.  virescens  '^Qtma.thermalis  Briigg.,  a 
plant  from  Bethlehem,  Pa.,  rather  shorter-jointed  than  usual  for 
this  species. 

As  P.  B.-A.,  No.  1193,  is  distributed  a  very  long  and  spar- 
ingly branched  plant  from  California,  under  the  name  of  C.  cris- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  355 

pata  forma  subsimfylcx  Collins.  It  is  quite  close  to  forma  longis- 
si)/i(t  (Kiitz.)  Rabenhorst,  1868,  p.  337.  This  form  seems  to  be 
quite  common  in  California  ;  the  fronds  remaining  attached  to 
stones,  etc.  in  running  water  until  they  have  reached  their  full 
growth,  sometimes  as  much  as  a  meter  ;  the  branching  is  rather 
distant,  the  ramuli  are  short,  with  cells  4-8  diam.  long. 

50.  C.    SECUXDA    Kiitzing,    1849,    p.    411;    P.    B.-A.,    No. 
1230.     Forming  dense  masses;  main  filaments  elongate,  sinu- 
ous, sparingly  branched  alternately  or  subdichotomously  ;  bear- 
ing long  secund  series  of  ramuli,  normally  one  from  each  cell  of 
the  filament  ;  long  below,  becoming  gradually  shorter  towards 
the  tip;  cells  in  main  filaments  and  branches  90-125  fj.  diam., 
3-5  diam  long,  cylindrical  or  somewhat  contorted  ;    in  ramuli 
20-40  p.  diam.,  4-8  diam  long,  cylindrical  or  slightly  swollen  ; 
ramuli  tapering  to  the  subacute  tip.     California.  Europe. 

No  authentic  specimen  of  this  species  being  accessible,  there 
is  naturally  some  doubt  as  to  the  identification  ;  the  California!! 
plant  formed  floating  masses  in  a  watering  trough  at  No.  Berke- 
ley, Cal.,  while  Kiitzing's  plant,  though  included  by  him  among 
the  fresh  water  algae,  was  found  by  Suhr  in  brackish  water  in 
Denmark.  The  description  agrees  well  with  the  plant,  and 
there  seems  to  be  no  other  described  species  in  which  the  latter 
could  be  included  ;  to  avoid  making  a  new  species,  the  present 
name  is  applied.  In  our  plant  there  is  a  remarkable  contrast 
between  the  coarse  cells  of  the  large  filaments  and  the  delicate 
cells  of  the  ramuli  ;  it  seems  like  young  plants  of  C.  crispata 
growing  out  of  old,  battered  stems  of  C.fracta,  and  emphasizes 
our  lack  of  knowledge  of  any  of  these  species,  through  all  their 
life  history. 

51.  C.   INSIGNIS   (Ag.)    Kiitzing,    1845,   p.   217;   1854,    PI. 
XXXVIII,    fig.   i  ;    P.  B.-A.,    No.    868.     Forming   extensive 
strata  ;    filaments    straight    or   nearly   so,    usually    very   little 
branched,  75-120  p  diam.;  branches  down  to  40  >  diam.;  cells 
4-6  diam.  long,  somewhat  swollen.     In  quiet  water,  California. 


Fairly  distinct  by  the  stout,  straight,  little  branched  filaments. 
Our  plant  seems  to  belong  to  the  type,  but  any  of  the  numerous 
varieties  may  be  expected. 

52.  C.  HOLSATICA  Kiitzing,  1849,  p.  414;  C.aegagropild  P. 
B.-A.,  No.  164.  Forming  by  the  dense  and  irregular  branch- 


356  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

ing,  spherical  masses,  1-3  cm.  diam.,  lying  loose  on  the  bottom, 
or  slightly  attached  by  rhizoidal  growths  ;  filaments  about  45  p. 
diam.  at  base,  up  to  90  p.  in  the  main  branches,  ramuli  45  p., 
terminal  cells  clavate  or  blunt-lanceolate,  often  swollen  near  the 
tip  ;  cells  mostly  somewhat  larger  at  the  top  than  at  the  base  ; 
branches  quite  irregularly  placed,  densely  packed.  Mass. 

Europe. 

In  the  only  reported  American  locality,  this  species  was 
washed  ashore  in  the  form  of  small,  hard,  globular  masses, 
each  a  densely  branched  individual.  Other  forms  of  the  Aega- 
gropila  type  probably  occur,  but  no  definite  reports  are  to  be 
had. 

53.  C.  UBERRIMA  Lambert  ms.;  P.  B.-A.,  No.  1531.  Frond 
minute,  seldom  over  i  cm.  high,  attached  below  by  short, 
irregular,  branching  filaments  ;  main  filaments  30-50,  rarely 
60  p.  diam.,  cells  3-10  diam.  long;  densely  branched,  branches 
opposite  or  alternate,  erect  or  patent,  issuing  from  any  part  of  a 
cell ;  the  first  cross  wall  either  at  the  base  of  a  cell  or  higher 
up  ;  erect  branches  often  connate  with  each  other  or  with  the 
main  stem  for  some  distance  ;  ultimate  ramuli  straight  or  curved, 
15-20  p.  diam.,  cells  5-10  diam.  long;  terminal  cell  slightly  at- 
tenuate, with  rounded  apex.  Production  of  zoospores  and 
gametes  very  abundant,  in  terminal  or  intercalary  cells,  in  all 
parts  of  the  frond ;  new  growth  from  cell  below  often  passing 
through  the  empty  sporangium. 

A  rather  anomalous  species,  presenting  some  remarkable 
peculiarities ;  this  notice  is  merely  preliminary ;  a  detailed 
account  of  the  plant  is  soon  to  be  published  by  Professor  Lam- 
bert, who  has  had  it  under  culture  at  the  Botanical  Laboratory 
of  Tufts  College. 

Among  the  doubtful  species  of  Cladophora  must  be  reckoned 
the  following. 

C.  trinitatis  Kiitzing,  1849,  p.  420. 

C.  Morrisiae  Harvey,  1858,  p.  78,  PI.  XLV.B. 

Aegagropila  Montagnei  Kiitzing,  1849,  p.  415  ;  1855,  p.  14, 
PI.  LXV,  fig.  2. 

Spongopsis  saccata  Kiitzing,  1849,  p.  380;  1853,  p.  17,  PL  L, 
fig.  i. 

4.     SPONGOMORPHA  Kiitzing,  1843,  p.  273. 

Fronds  of  branching,  monosiphonous  filaments,  larger  at  the 
tip  than  below,  terminal  cell  longer  than  other  cells,  intercalary 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  357 

cell  division  general,  cells  other  than  terminal  usually  short  ; 
special  descending  rhizoidal  branches,  or  special  spine-like  or 
hooked  branches  present,  more  or  less  matting  the  tufts  to- 
gether ;  cells  in  one  species  uninucleate.  Otherwise  as  in  Cla- 
dophora.  Marine. 

The  special  branches  give  this  genus  a  higher  rank  than  that 
of  Cladophora,  and  the  predominance  of  intercalary  cell  division 
also  distinguishes  it.  The  species  are  most  abundant  in  arctic 
waters,  not  extending  south  beyond  the  temperate  zone.  The 
species  from  the  Atlantic  here  included  in  Spongomorpha  would 
be  placed  by  Scandinavian  authors  under  Acrosiphonia,  follow- 
ing the  monograph  of  that  genus  by  Kjellman,  1893,  except  that 
if  Wille,  18993,  is  followed,  the  multiuucleate  species  are  in- 
cluded in  Acrosiphonia,  and  Spongomorpha  is  used  only  for  the 
uninucleate  Cladophora  lanosa.  In  Jonsson,  1904,  the  algae  of 
East  Greenland  are  thus  divided,  but  the  old  specific  names 
arcta  and  lanosa  disappear  entirely,  Acrosiphonia  incurva  and 
Spongomorpha  vcrnalis  appearing  instead.  It  is  hard  to  see 
what  principle  justifies  this.  Spongomorpha  dates  to  Kiitzing, 
1843;  Acrosiphonia  to  J.  G.  Agardh,  1846;  the  specific  names 
incurva  and  vernalis  are  of  Kjellman,  1893,  while  arcta  dates 
from  Dillwyn,  1809,  and  lanosa  from  Roth,  1806. 

KEY  TO  THE  SPECIES  OF  SPONGOMORPHA. 

i.     Spinous  or  hooked  branches  present.  2. 

i.     Spinous  or  hooked  branches  wanting.  4. 

2.     Branches  not  spinous  ;  tufts  little  matted.          i.     S.  duriuscula. 

2.     Branches  spinous  ;  mature  tufts  densely  tnatted.  3. 

3.     Filaments  100  /u  diam.  at  tip.  6.     S.  spinescens. 

3.     Filaments  200  /*  diam.  at  tip.  ?•'  S.  coalita. 

4.     Filaments  200-500  M  diam.  at  tip.  2.     5.  hystrix. 

4.     Filaments  less  than  150  M  diam.  at  tip.  5- 

5.     Main  filaments  and  branches  obtuse.  6. 

5.     Main  filaments  and  branches  blunt-pointed.  5.     S.  saxatilis. 

6.     Filaments  30-40  n  diam.  3-     •£•  lanosa. 

6.     Filaments  60-100  M  diatn.  4-     S.  arcta. 

i.  S.  duriuscula  (Rupr.)  nov.  comb.;  Cfadophora  alaskana 
Collins  in  Setchell  and  Gardner,  1903,  p.  228;  P.  B.-A.,  No. 
917.  Tufts  15-25  cm.  high,  erect,  main  filaments  firm,  straight, 
with  thick,  striate  walls,  200-250  /«.  diam.  below,  300  at  tip; 
articulations  %-\^  diam.  long,  2-3  diam.  at  the  blunt  tips; 
branches  similar,  erect,  scattered  or  in  secund  series  of  two  or 


358  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

more  ;  near  the  base  of  the  tuft  more  slender,  150-200  ^  diam., 
with  thinner  walls,  not  striate,  with  numerous  short,  patent 
or  recurved  ramuli,  scattered  or  secund.  On  stony  beaches, 
lower  Ijtoral  and  upper  sublitoral.  Alaska. 

A  coarse  species,  but  not  matted  like  most  species  of  Spongo- 
morpha  ;  it  might  be  a  question  whether  it  belongs  in  this  genus 
or  in  Cladophora ;  but  the  filaments  usually  larger  at  the  tip, 
never  tapering,  the  cells  short  below,  longer  above,  indicate  the 
present  genus.  Since  the  publication  of  Cladophora  alaskana  it 
has  been  possible  to  examine  authentic  specimens  of  Ruprecht's 
Conferva  duriuscula,  and  there  is  no  doubt  of  the  identity ; 
Ruprecht's  description,  however,  is  so  scanty  that  no  decision 
was  possible  from  it ;  De  Toni  placing  the  species  in  Chaeto- 
morpha. 

2.  S.  HYSTRIX  Stromfelt,    1887,  p.   54;     Cladophora  hystrix 
P.  B.-A.,  No.  982.     Fronds  rich  green,  in  rather  dense  tufts, 
filaments  straight,  very  erect,  except  those  at  the  base  of  the 
tuft,  which  are  somewhat  more  open  ;  about  100-300  /*  diam.  at 
the  base,  200-500  p.  diam.  at  the  tip  ;  cells  up  to  4  diam.  long  at 
the  tip,  %-iyz  diam.  long  below  ;  rhizoidal  branches  fairly  com- 
mon in  the  older  parts,  40-70  /u,  diam.,  cells  3-10  diam.  long. 

Resembling  5".  arcta,  but  stouter  and  with  shorter  cells ;  a 
distinctly  arctic  species,  found  on  the  Massachusetts  coast  only 
in  a  reduced  form,  while  5*.  arcta  is  practically  the  same  in 
Greenland  as  in  Long  Island  Sound.  Three  forms  are  reported 
from  Greenland.  . 

Forma  typica  (Jonsson)  nov.  comb.  ;  Acrosiphonia  hystrix 
forma  typica  Jonsson,  1903,  p.  368.  Fronds  up  to  15  cm.  high, 
filaments  300-500  p.  diam.,  not  much  entangled. 

Forma  littoralis  (Jonsson)  nov.  comb.  ;  Acrosiphonia  hystrix 
forma  littoralis  Jonsson,  1903,  p.  370.  Tufts  4-10  cm.  high, 
filaments  200-300  /u  diam.,  considerably  entangled. 

Forma  debilis  (Rosenv.)  nov.  comb.  ;  Cladophora  arcta  forma 
debilis  Rosenvinge,  1893,  p.  908.  Tufts  not  over  10  cm.  high, 
with  few  long  branches,  but  many  short,  subsimple,  often 
secund  branches,  of  about  equal  length. 

3.  S.   LANOSA    (Roth)    Kiitzing,    1849,    p.  420 ;    Cladophora 
lanosa  Harvey,  1846-51,  PI.  VI;    1858,  p.  76;   Farlow,    1881,  p. 
51  ;   P.  B.-A.,  No.  661.     Fronds  fastigiate,   erect,   light   green, 
not   over   5  cm.  high,  30-40  //,  diam.,    branches   erect,  usually 
arising  some  distance  below  top  of  cell ;  cells  uninucleate,  2-6 


THE  GRKKN  AI.GAR  OF  NORTH  AMERICA  359 

diatn.  long,  more  or  less  matted  at  the  base  by  descending 
rhizoidal  filaments,  slightly  smaller  than  the  main  filaments. 
On  various  algae.  Greenland  to  Conn.  J\urope. 

A  spring  plant,  forming  very  regular  rounded  tufts  on  vari- 
ous algae,  the  tufts  becoming  detached  as  the  plant  matures. 
It  is  noteworthy  as  having  only  one  nucleus  to  a  cell,  while  as 
far  as  observed  all  other  species  of  Spongomorpka  and  Clado- 
phora  have  normally  two  or  more  nuclei.  It  is  possible  that 
some  of  the  Alaskan  species  may  also  be  uninucleate,  but  no 
certainty  can  be  had  from  dried  specimens.  On  the  other  hand, 
single  uninucleate  cells  are  occasionally,  though  rarely,  found 
in  other  species  ;  and  as  apart  from  this  character  this  species  is 
in  everything  conformable  to  Spongomorpha,  it  does  not  seem 
necessary  to  institute  a  separate  genus  for  it. 

Var.  UNCIAUS  (Fl.  Dan.)  Kjellman,  1883,  p.  306;  Cladophora 
uncial  is  Harvey,  1846-51,  PI.  CCVII  ;*  1858,  p.  77  ;  C.  lanosa 
var.  nncialis  Farlow,  1881,  p.  51  ;  P.  B.-A.,  No.  77.  Tufts  ir- 
regular in  outline,  growing  on  rocks,  not  floating  away  when 
mature,  but  persistent  in  a  coarse  and  faded  state.  Me.  to 
Conn.  Europe. 

4.  S.  ARCTA  (Dillw.)  Kiitzing,  1849,  p.  417;  Cladophora 
arcta  Harvey,  1846-51,  PI.  CXXXV ;  1858,  p.  75;  Farlow, 
1881,  p.  50;  P.  B.-A.,  Nos.  224,  815.  Fronds  rich  green,  in 
dense  fastigiate  tufts,  up  to  15  cm.  high;  filaments  erect,  stiff, 
60-100  ^  diam.  at  tips,  cells  4-6  diam.  long  ;  below  smaller,  cells 
1^-3  diam.  long  ;  much  branched,  branches  erect  or  appressed, 
obtuse  orclavate  ;  rhizoidal  descending  branches  40-60  n  diam., 
cells  2-6  diam.  long,  firmly  matting  together  the  lower  part  of 
the  tuft.  On  exposed  rocky  shores  in  spring.  Greenland  to 
N.  J.  ;  Alaska  to.  Wash.  Europe. 

A  common  plant,  the  rounded  rich  green  tufts  being  very 
handsome  while  the  plant  is  young  ;  later  it  becomes  coarse 
and  faded.* 

Forma  conglutinata  nov.  comb.  ;  Cladophora  arcta  forma 
convlutinata  Collins  in  Setchell  and  Gardner,  1903,  p.  225. 
Filaments  adhering  in  pointed,  Symploca-like  tufts ;  patent 
acute  branches  occasionally  found  at  the  base  of  older  plants. 
Alaska  to  Wash. 

*Var.  penicilliformis  Foslie  in  Wittr.  and  Nordst.,  Alg.  Exsicc.,  No. 
613,  a  rather  slender  form  with  terminal  sporangia,  is  doubtfully  re- 
ported from  Greenland,  Roseuvinge,  1893,  p.  908;  Jbnsson,  1904,  p.  49. 


360          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Forma  PULVINATA  Foslie,  1890,  p.  130;  Cladophora  arcta 
forma  pulvinata  P.  B.-A.,  No.  918.  Filaments  short,  of  uni- 
form length,  forming  level-topped  pulvinate  masses.  Alaska. 

Northern  Europe. 

5.  S.  saxatilis  (Rupr.)  nov.  comb.  ;  Cladophora  saxatilis 
Setchell  and  Gardner,  1903,  p.  223;  P.  B.-A.,  No.  921.  Fronds 
dense  but  not  much  matted  together;  filaments  80-120  /x, 
diam.,  about  the  same  diam.  throughout,  cells  below  1-3  diam. 
long,  above  3-6  diam.  ;  terminal  cell  sometimes  10-12  diam.  ; 
branching  di-  trichotomous,  with  occasional  lateral  branches, 
divisions  erect,  somewhat  acute  or  tapering,  but  with  rounded 
tip  ;  older  parts  with  descending  rhizoidal  filaments,  about  half 
the  diam.  of  the  filaments  from  which  they  spring,  and  with 
longer  cells,  sometimes  10-12  diam.  long.  Alaska  to  Wash. 

Kamtschatka . 

Varying  considerably  in  size  of  filaments,  length  of  cells, 
erect  or  patent  branches,  but  on  the  whole  with  longer  cells  than 
most  of  the  species  of  Spongomorpha.  The  branches  increase 
little  if  any  in  size  towards  the  end,  and  the  terminal  cell  is  not 
sharply  truncate.  The  four  species  of  Ruprecht,  1856,  Con- 
ferva Chainissonis,  C.  Mertensii,  C.  viminea  and  C.  saxatilis^ 
seem  to  be  merely  varieties,  forms  or  states  of  growth  of  one 
species,  C.  saxatilis  representing  stouter  or  older  forms,  C.  Cha- 
missonis  more  delicate  ;  the  two  other  species  range  between. 
Little  could  be  known  from  Ruprecht's  short  descriptions,  but 
authentic  specimens  in  Herb.  Farlow  justify  the  present 
arrangement. 

Var.  Chamissonis  (Rupr.)  nov.  comb.;  Cladophora  Cha- 
missonis  Harvey,  1858,  p.  75  ;  P.  B.-A.,  No.  920.  Filaments 
40-60  /x  diam.,  cells  3-4  diam.  long,  nodes  constricted;  cells 
slightly  shorter  towards  the  base.  Alaska  to  Wash. 

Kamtschatka . 

Smaller  and  more  delicate  than  the  type,  but  not  otherwise 
distinct. 

6.  S.  SPINESCENS  Kiitzing,  1849,  p.  418;  1854,  PL  LXXV, 
fig.  2  ;  Cladophora  arcta  var.  centralis  P.  B.-A.,  No.  721.  Fila- 
ments about  80  /u  below,  i oo  /A  at  tip  ;  cells  j^-i  diam.  long  below, 
2  diam.  long  at  tip ;  normal  erect,  somewhat  obtuse  branches 
abundant ;  also  patent  and  acute  branches,  either  short  and 
spine-like,  or  long,  hooked,  revolute  and  circinate,  uniting  the 
filaments  into  branching  rope-like  tufts ;  descending  rhizoidal 
branches  less  common.  Fig.  126.  Me.  to  Mass.  ;  Alaska. 

Northern  Eiirope. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  361 

Often  confused  with  S.  a  ret  a,  which  in  its  older  stages  is 
much  matted ;  but  in  that  species  the  filaments  are  united  by 
the  descending  rhizoidal  branches  only  ;  in  5".  spincsccns  chiefly 
by  the  hooked  branches. 

7.  S.  coalita  (Rupr.)  nov.  comb.  ;  Cladophora  coalita  P. 
B.-A.,  No.  819;  C.  scopacformis  Harvey,  1858,  p.  75  ;  P.  B.-A., 
No.  922.  Fronds  at  first  loosely  tufted,  but  soon  forming  dense, 
rope-like  branching  tufts,  up  to  30  cm.  long  ;  at  first  bright, 
later  dull  or  yellowish-green  ;  filaments  100-250  //.  diam.  in  the 
terminal  cell  ;  branching  dichotomous  below,  irregularly  alter- 
nate above  ;  all  branches  of  this  class  erect,  with  blunt  or  trun- 
cate ends ;  also  present,  except  in  very  young  plants,  abundant 
patent,  tapering,  very  acute,  hooked  or  circinate  branches,  by 
which  all  the  older  parts  are  densely  matted  together  ;  cells  l/z-i 
diam.  long  in  the  lower  part  of  older  plants,  2-3  diam.  in 
younger  plants,  and  even  6-10  diam.  in  the  active  terminal  cell. 
Alaska  to  Cal.  Kamtschatka. 

The  hooked  branches  distinguish  this  species  from  all  others 
except  6".  spinescens,  which  is  a  smaller  plant,  with  filaments 
about  half  the  size  of  those  in  5".  coalita.  In  the  review  of  this 
group  in  Setchell  and  Gardner,  1903,  p.  227,  Cladophora  coalita 
and  C.  scopaeformis  were  considered  distinct  species,  but  on  look- 
ing over  material  from  various  points,  and  collected  at  various 
seasons,  it  seems  impossible  to  keep  them  separate.  C.  polaris 
Harvey  would  seem  to  be  the  very  young  plant,  with  normal 
erect  branches  only,  and  with  texture  delicate.  When  the 
plant  has  nearly  reached  its  full  growth,  it  is  C.  scopaeformis, 
with  long,  green,  actively  dividing  terminal  cell  to  each  normal 
branch  ;  in  the  lower  part  of  the  filaments  the  cells  are  consid- 
erably shorter,  and  the  walls  cartilaginous ;  hooked  branches 
are  plentiful.  At  a  still  later  stage  the  terminal  cells  have 
ceased  to  grow  at  the  tip  as  fast  as  new  cells  have  been  cut  off 
below ;  they  are  but  little  distinct  from  the  other  cells,  either  in 
length  or  texture.  The  division  of  the  lower  cells  has  gone  on 
until  most  of  them  are  shorter  than  their  breadth  ;  hooked 
branches  have  been  developed  until  the  greater  part  of  the 
plant  is  now  shaggy  with  them.  The  plant  is  now  typical 
Conferva  coalita  of  Ruprecht.  C.  cartilaginea  Ruprecht  very 
likely  should  be  here  included;  but  the  description,  1856,  p. 
404,  is  hardly  sufficient,  and  no  authentic  specimens  are  ac- 


362          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

cessible.  The  specimens  from  Monterey,  referred  to  Cladophora 
cartilaginea,  Setchell  and  Gardner,  1903,  prove  to  belong 
elsewhere. 

Spongomorpha  rhizophora  Kiitzing,  1849,  p.  418  ;  18553,  p.  16, 
PL  LXXVI,  fig.  2,  is  a  doubtful  species. 

4.     CLADOPHOROPSIS  Borgesen,  1905,  p.  288. 

Frond  filamentous,  without  distinct  axis ;  .basal  filaments 
prostrate,  attached  by  multicellular  holdfasts ;  erect  filaments 
with  more  or  less  abundant  branching,  with  apical  growth  ;  a 
branch  issuing  directly  under  a  cross  wall,  no  wall  being  formed 
in  the  branch  until  the  latter  has  attained  a  considerable  length, 
and  then  normally  not  at  the  base  of  the  branch ;  branches 
occasionally  arising  by  aplanospore-like  bodies  formed  in  the 
cell,  and  pushing  out  through  the  cell  wall  ;  cells  multinucle- 
ate,  with  net-shape  chromatophore  and  many  pyrenoids  ;  repro- 
duction unknown. 

This  genus  is  practically  intermediate  between  Cladophora 
and  Siphonocladus,  showing  the  close  relationship  of  the  Clado- 
phoraceae  and  the  Valoniaceae.  It  has  the  habit  of  a  Clado- 
phora of  the  subgenus  Aegagropila,  but  the  branches  have 
normally  no  partition  at  the  base.  In  this  latter  respect  it 
agrees  with  Siphonocladus ,  but  the  frond  does  not  originate  in  a 
single  clavate  cell.  The  secondary  branching  reminds  one  of 
Valonia.  We  have  only  one  species. 

C.  MEMBRANACEUS  (Ag.)  Borgesen,  1905,  p.  288,  figs.  8-13  ; 
Cladophora  membranacea  Harvey  1858,  p.  73  ;  Siphonocladus  mem- 
branaceus  Vickers,  1908,  p. 20,  PL  XVII ;  P.  B.-A.,  No.  225. 
Fronds  densely  matted,  up  to  10  cm.  high,  the  holdfasts  of  the 
prostrate  filaments  large  and  well  developed ;  erect  filaments 
about  i8o/u,  diam.,  with  branches  at  first  alternate,  later  secund  ; 
partitions  formed  at  irregular  but  usually  long  intervals,  the 
terminal  cell  usually  many  diam.  long  ;  branches  often  adher- 
ing by  tenacula  similar  to  the  basal  holdfasts,  but  shorter  ; 
branches  arising  from  aplanospore-like  formation  not  uncom- 
mon. Fig.  129  Fla.,  W.  I. 

6.     PITHOPHORA  Wittrock,  1877,  p.  48. 

Fronds  filamentous,  monosiphonous,  branching,  branches  is- 
suing from  below  the  top  of  the  cells ;  cells  cylindrical  or 
swollen,  multinucleate,  with  net-like  chromatophore  and  many 
pyrenoids ;  asexual  reproduction  by  akinetes,  terminal  or  inter T 
calary  in  the  filaments,  formed  by  the  division  of  a  vegetative 
cell,  the  upper  half  forming  the  akinete,  the  lower  half  remain- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  363 

ing  usually  sterile  ;  the  germinating  akinete  dividing  into  two 
parts,  of  which  one  develops  a  short  rhizoid,  the  other  the 
initial  cauloid  filament  of  the  future  plant. 

A  genus  of  chiefly  tropical  and  subtropical  fresh  water  plants, 
closely  allied  to  Cladophora,  but  the  reproduction  by  akinetes 
appears  to  take  the  place  of  the  reproduction  by  zoospores  and 
gametes.  Sterile  plants  are  practically  indistinguishable  from 
Cladophora,  but  a  fertile  frond  of  Pithophora  is  unmistakable 
for  anything  else.  Specific  distinction,  however,  is  not  always 
easy.  The  species  being  naturally  tropical,  are  often  found  in 
greenhouses  where  tropical  plants  are  cultivated. 

KEY  TO  THE  SPECIES  OF  PITHOPHORA. 

i.     Intercalary  akinetes  all  of  about  the  same  shape.  2. 

i.     Intercalary  akinetes  varying  in  the  same  plant;  cylindrical,  cask- 
shaped,  obovoid  or  irregular.  4. 

2.     Main  filament  seldom  under  150  n  diam.  i.     P.  aequalis. 

2.     Main  filament  less  than  100  M  diam.  3. 

3.     Special  helicoidal  cells  frequent.  3.     P.  Cleveana. 

3.     Special  helicoidal  cells  wanting  or  very  rare.          2.     P.  oedogonia. 

4.     Main  filaments  about  165  M  diam.  5.     P.  Roettleri. 

4.     Main  filaments  seldom  reaching  100  n  diam.  4.     P.  varia. 

1.  P.  AEQUALIS  var.  FLORIDENS1S  Wolle,    1887,    p.   131,    PI. 

CXIV,  figs.  1-5.  Main  filaments  in  fertile  plant  150-175/4  diam., 
with  a  few  elongate  branches,  and  many  short  branches ;  cells 
more  or  less  swollen  ;  akinetes  solitary  or  rarely  two  together, 
intercalary  in  the  main  filaments  or  the  long  branches,  rarely 
terminal ;  intercalary  akinetes  cask-shaped,  with  somewhat 
rounded  top,  about  215 X  120/4  ;  terminal  akinetes  cask-shaped, 
conical  or  sometimes  rounded  above,  about  270X90  /*.  Fla. 

The  type  is  found  in  So.  America,  and  has  main  filaments 
seldom  exceeding  100  /x  diam.,  and  akinetes  slightly  larger  than 
in  the  variety. 

2.  P.  OEDOGONIA  (Mont.)   Wittrock,    1877,  p.'  55,   PI.  VI, 
figs.  1-6;  including  var.  vaucherioidcs  Wolle,    1887,   p.  130,   PL 
CXIII,  figs.  1-7.     Main  filaments  about  70  p.  diam.,  branches  of 
three  orders  scattered  or  opposite  ;  branches  occasionally  issu- 
ing from  the  short  cell  below  the  akinete  ;    akinetes  solitary, 
rarely  in  twos,  intercalary  or  terminal ;  intercalary  akinetes  cask- 
shaped,    about    230X115   /"•;    terminal   akinetes  cask-shaped, 
above  shortly  acuminate,  with  rounded  apex,  about  215X95^-* 
Fig.  113.     Pa.,  N.  J.,  Neb.  So.  America. 

*P.affinis  Nordstedt,  1878,  p.  19;  Saunders,  1894,  p.  66,  is  reported 
from  Neb.,  but  no  specimens  have  been  seen.  It  was  described  from 


'364          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

3.  P.  CLEVEANA  Wittrock,  1877,  p.  58,  PI.  II,  figs.  13-15; 
PI.  IV,  figs.  12-18;  PL  V,  figs.  1-8.     Main  filaments  about  75  p. 
diam.,  branches   usually  of  the   first  order   only,   occasionally 
with  a  few  short,  scattered  or  opposite  branches  of  the  second 
order ;    special  helicoid  cells  frequent ;  akinetes  intercalary  or 
terminal,   solitary,    rarely  in  twos ;    intercalary   akinetes  cask- 
shaped,  2oo-26oX  100-160  yu.,  or  subcylindrical,  about  165X70  p.; 
terminal  akinetes  cask-shaped  with  shortly  acuminate  rounded 
apex,  175-240X90-105  /u..     Fla.,  St.  Thomas,  Barbados. 

4.  P.  VARIA  Wille,  P.  B.-A.,  No.  983  ;  P.  Kewensis  Tilden, 
Amer.  Algae,  No.  39.     Filaments  75-105  p.,   primary  and  sec- 
ondary branches  about  the  same  ;  terminal  cells  43-70  /u.,  rarely 
ending  in  helicoids ;  akinetes  i-3-seriate,  with  wall,  especially 
end  wall,  quite  thick,  terminal  and  intercalary,  arising  in  main 
stem  or  in  branches  of  any  order ;  terminal  akinetes  ovoid,  with 
pointed    tip,    150-210X64-69  p. ;    intercalary   70-240X60-112  p.; 
ovoid,  cylindrical  or  irregular.     111.,  Mich.,  Minn. 

The  only  species  of  Pithophora  native  in  colder  regions. 
Nearest  related' to  P.  Cleveana  Wittr.,  but  differing  in  several 
characters.  The  akinetes  occur  even  in  the  shortest  branches, 
some  branches  consisting  of  two  akinetes  and  nothing  else. 
The  form  of  the  akinetes  differs  much  in  the  same  branch,  and 
series  of  2  or  3  are  found  including  every  possible  combination 
of  cylindrical,  ovoid  and  irregular  forms.  P.  Kewensis  Tilden, 
No.  39,  is  identical  with  P.  varia  ;  P.  Kewensis  Wolle,  '1887,  p. 
131,  is  founded  on  sterile  plants,  and  cannot  be  considered 
reliable. 

5.  P.  ROETTLERI  (Roth)  Wittrock,    1877,  p.  66,   PI.  I,  figs. 
12-20;   PI.  V,  figs,  ii  and  12  ;   Cladophora  Engelmanni  Kiitzing, 
1849,  p.  411.     Main  filaments  about  165  p-  diam.,  branching  of 
three  orders ;  branches  of  the  first  order  in  whorls  of  three  or 
more.;  of  second  and  third  orders  scattered  or  opposite;  akin- 
etes solitary,   rarely   in  twos,   intercalary  or  terminal ;    in  the 
main  filaments  of  irregular  and  varying  shape,  about  210X190 
fj. ;  in  the  branches  cask-shaped,  about  260X150^,  or  cylindri- 
cal, about   140X80 /A;  terminal  akinetes  obovoid  with  truncate 
base,  about  210X150  /A,  or  more  rarely  subconical  with  rounded 
apex,  about  250X90  /A.     Cuba,  Ark.,  in  warm  springs. 

Asia,  So.  America. 

Hawaiian  specimens,  and  differs  from  P.  oedogonia  by  less  compound 
branching,  no  branches  from  cells  below  akiuetes,  and  akinetes  varying 
much  in  size,  but  proportionally  stouter  than  in  P.  oedogonia. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  365 

7.     ANADYOMENE  L,amouroux,  1816,  p.  365. 

Frond  membranaceous,  stipitate,  membrane  consisting  of 
cells  of  two  shapes,  the  larger,  elongate  cells  forming  a 
branching  framework,  radiating  from  the  base  and  paltnately 
divided  ;  smaller  roundish  or  ovoid  cells  issuing  from  the  frame- 
work and  filling  its  intervals,  forming  a  continuous  membrane  ; 
in  some  species  the  membrane  is  of  two  layers  of  these  smaller 
cells.  Zoospores  formed  in  large  numbers  in  the  smaller  cells, 
escaping  through  an  opening.  Marine. 

The  branching  is  beautifully  symmetrical  in  the  fronds  of  this 
genus,  showing  plainly  under  a  pocket  lens,  or  even  to  the 
naked  eye.  We  have  two  species,  one  found  throughout  the 
warmer  Atlantic,  the  other  recorded  once  only,  at  some  point, 
not  definitely  known,  in  the  Gulf  of  Mexico. 

KEY  TO  THE  SPECIES  OF  ANADYOMENE. 

I.     Ribs  of  a  single  series  of  cells,  each   cell  bearing  above  normally 
three  or  more  similar  cells,  paltnately  arranged. 

i.     A.  stellata. 

i.     Ribs  composed  of  several  contiguous  series  of  cells,  branching  only 
at  considerable  intervals.  2.     A.  Menziesii. 

1.  A.  STELLATA  (Wulfen)  Agardh,   1822,  p.  400;  Vickers, 
1908,  p.  21,  PI.  XXI  ;  P.  B.-A.,  No.  169  ;  A.  flabellata  Harvey, 
1858,  p.  49,  PI.  XLIV.A.     Fronds  often  tufted,  up  to  10  cm. 
diam.,  usually  ovate  or  reniform  in  outline,  in  older  plants  often 
much  lobed  ;  of  a  single  thickness  of  cells  ;  the  stipe  produced 
into  palmately  arranged  clavate  cells,  forming  similarly  dividing 
series  throughout  the   frond ;    interspaces   filled   with    smaller 
oblong  cells,  issuing  at  right  angles  to  the  ribs,  and  forming  a 
continuous  membrane.     Fig.  125.     Fla.,  W.  I. 

Mediterranean,  So.  America. 

J.  G.  Agardh,  1886,  p.  125,  mentions  two  forms;  f.  normalis 
and  f.  luxurians,  the  former  with  slenderer,  longer,  clavate  or 
cylindrical  rib-cells;  the  latter  with  stouter,  shorter,  .ovoid 
cells  ;  but  he  considers  the  latter  form  merely  a  luxuriant  state 
of  the  former. 

2.  A.  MENZIESII  Harvey,  1858,  p.  50;   Grayemma  Menziesii 
J.  E.  Gray,  1866,  p.  51,  PI.  XLIV,  figs,  i  and  2.     Frond  up  to 
25  cm.  diam.,  margin  lobed,  the  stout  ribs  terminating  in  the 
lobes ;  rib  formed  of  a  bundle  of  parallel  short-jointed  filaments, 
the    marginal   ones   giving   out  radiating   branches  of    smaller 
cells,  which  form  the  membrane  between  the  ribs. 

Dredged  in  40  meters  in  the  Gulf  of  Mexico,  iu  1802,  by 
Archibald  Menzies  ;  not  since  recorded. 


366          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

8.  MICRODICTYON  Decaisne,  1839,  p.  115. 
Frond  a  sessile,  membranaceous  net-work,  formed  of  mono- 
siphonous  filaments,  densely  branching  in  one  plane  in  a  radiate 
manner,  the  tip  of  one  branch  attaching  itself  to  another  branch 
by  a  terminal  thickening ;  irregular,  angular  open  spaces  be- 
tween the  cells.  Asexual  (?)  reproduction  by  zoospores,  formed 
in  any  cell.  Marine. 

KEY  TO  THE  SPECIES  OF  MICRODICTYON. 

i.     Cells  rarely  equalling  200 /i*  diam.  i.     M.  Agardhianum. 

i.     Cells  up  to  500  M  diam.  2.     M.  crassum. 

1.  M.  AGARDHIANUM  Decaisne,  1839,  p.  115;  M.  umbilica- 
tum  Hauck,    1885,   p.  467,  fig.  203.    Frond  delicately   membra- 
naceous, filaments  50-200  p.  diam.,  main  veins  rather  distinct, 
radiate,  branches  patent;   cells  usually  2-4   diam.  long.     Fig. 
132.     Guadeloupe  Island,  Cal.  Europe. 

Our  plant  seems  to  agree  with  the  common  form  of  the  Medi- 
terranean, which  is  often  known  as  M.  umbilicatum ;  but  there 
is  a  question  whether  the  European  plant  is  the  same  as  Conferva 
umbilicata  Velley,  from  the  Hawaiian  Islands ;  Decaisne's 
specific  name  is  here  used  as  the  first  one  fairly  certain. 

2.  M.  CRASSUM  J.  G.  Agardh,  1894,  p.  107.     Rather  coarse 
in  texture,  filaments  up  to  500  p.  diam.  ;    cells  seldom  16nger 
than  broad,  somewhat  moniliform  ;  branches  of  different  orders 
little  distinct  in  size  or  position.     Bahamas. 

A  much  coarser  plant  than  our  other  species. 

9.     CYSTODICTYON  Gray,  1866,  p.  72. 

Frond  a  perforated  membrane  with  a  framework  of  radiating, 
monosiphonous,  articulate  filaments,  attached  as  in  Microdictyon  ; 
the  intervals  being  partly  filled  by  smaller  cells,  with  open  cen- 
tral spaces ;  reproduction  unknown.  Marine. 

In  this  genus  there  is  the  same  network  of  radiate  filaments  as 
in  Microdictyon ;  but  there  are  also  many  short,  one  or  few 
celled  branches,  issuing  from  the  filaments  irregularly,  and 
attaching  by  thickened  tips. 

C.  PAVONIUM  J.  G.  Agardh,  1894,  p.  109;  P.  B.-A.,  No. 
666.  Frond  up  to  3  cm.  diam.  ;  main  filaments  radiating  from 
centers  in  various  parts  of  the  frond,  stout,  tapering,  openings 
rounded,  of  various  sizes.  Fig.  127.  Fla. 

10.     BOODLEA  Murray,  1890,  p.  243. 
Frond  as  in   Qadophora,  but   the  branches  attaching  them- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  367 

selves  one  to  another  by  the  thickened  tips,  forming  a  more  or 
less  spongy  frond. 

From  Cladophora,  Boodlca  is  distinguished  by  the  adherent 
tips  of  the  branches,  which,  however,  do  not  amount  to  a  dis- 
tinct organ  as  in  Stnivcti ;  from  Microdidyon  it  is  Distinguished 
by  branching  in  all  directions. 

B.  COMPOSITA  (Harv.  and  Hook.)  Brand,  1904,  p.  187,  PL 
VI,  figs.  28-35  !  Cladophora  composite  P.  B.-A.,  No.  722.  Form- 
ing spongy,  pale  green  tufts ;  filaments  soft,  pellucid,  dichoto- 
mous  below,  above  with  opposite  or  whorled  branches,  all  at 
wide  angles ;  cells  2-5  diam.  long ;  200-225  /*  diam.  below, 
about  120  /u.  in  the  ramuli  and  there  not  much  longer  than 
broad.  Fig.  128.  British  Columbia,  Cal. 

Hawaiian  and  other  Pacific  Islands. 

This  species  occurs  in  dense  masses  in  the  literal  zone ;  the 
cells  are  much  swollen,  either  ovoid  or  pyriform,  the  cell  wall 
thin  and  delicate.  The  ramuli  are  usually  opposite,  but  often 
whorled,  and  the  habit  is  much  like  one  of  the  branching 
Valonias. 

ii.     DICTYOSPHAERIA  Decaisiie,  1842,  p.  32. 

Frond  attached  by  rhizoids,  rounded,  solid  or  hollow,  con- 
sisting of  a  cellular  mass,  or  of  a  single  layer  of  closely  set, 
polygonal  cells,  attached  to  each  other  by  short  tenacula ; 
frond  increasing  in  size  by  the  division  of  the  cells  of  the  single 
layer,  or  by  externally  giving  off  dense  branches,  forming  an 
outer  layer,  the  older  layer  persistent  or  perishing  ;  reproduc- 
tion unknown. 

D.  FAVULOSA  (Ag.)  Decaisne,  1842,  p.  32  ;  Harvey,  1858,  p. 
50,  PI.  XLIV.B.  ;  Vickers,  1908,  p.  21,  PI.  XXII;  P.  B.-A., 
No.  124.  Frond  always  hollow,  hemispherical  or  oblong  in 
shape,  unless  broken  by  external  causes;  cells  5-6-angled,  up 
to  2  mm.  diam.  Fig.  137.  Fla.,  W.  I.,  Mexico. 

Indian  and  Pacific  Oceans. 

The  roundish,  light  green,  berry-like  fronds,  from  2  to  10  cm. 
diam.,  grow  attached  to  corals  and  rocks,  and  are  not  likely  to  be 
mistaken  for  anything  else. 

12.     HORMISCIA  Fries,  1835,  P-  327- 

Filaments  simple,  attached  at  the  base  by  growths  from 
within  the  cell,  or  from  the  cell  wall ;  cells  multinucleate,  all 
above  the  base  similar,  capable  of  division  and  of  producing 
zoospores ;  chrornatophore  covering  the  cell  wall,  entire  or  net- 


368          TUFTS  COLLEGE;  STUDIES,  VOL.  II,  No.  3 

like,  with  several  pyrenoids ;  asexual  reproduction  by  zoospores, 
many  in  a  cell,  obovoid,  extending  into  a  long  projection  below, 
and  with  4  cilia  above  ;  also  by  akinetes  formed  by  the  break- 
ing up  of  the  filaments  into  individual  cells,  with  thick  wall, 
either  producing  new  filaments  or  zoospores  ;  sexual  reproduc- 
tion by  bicili-  :e  gametes.  Marine. 

For  discussion  of  the  question  of  the  claims  of  the  generic 
names  Hormiscia  and  Urospora,  see  Hazen,  1902,  p.  147. 

KEY  TO  THE  SPECIES  OF  HORMISCIA. 

i.     Filaments  distinctly  clavate.  2. 

i.     Filaments  nearly  cylindrical.  4. 

2.     Cells,  except  at  extreme  base,  always  wider  than  long. 

4.     H.  crassa. 

2.     Cells  never  shorter  than  width.  3. 

3.     Greatest  diameter  135  /*.  5.     H.  incrassaia. 

3.     Greatest  diameter  500  fj..  2.     H.  Wormskjoldii. 

4.     Filaments  cylindrical ;  fertile  cells  not  swollen. 

3.     H.  Hart~ii. 
4.     Sterile  filaments  cylindrical  or  moniliform  ;  fertile  cells  distinctly 

swollen.  5. 

5.     Filaments  30-60 /x  diam.,  firm.  i.     H.  penicillifonnis. 

5.     Filaments  50-170  //.  diam.,  very  soft  and  lubricous. 

6.     H.  collabens. 

1.  H.  PENICILLIFORMIS   (Roth)   Fries,    1835,  p.   327;    Con- 
ferva Youngana  Harvey,  1846-51,  PI.  CCCXXVIII ;  Hormotri- 
chicm  speciosum  Harvey,    1858,  p.  90;    Ulothrix  isogona  Farlow, 
1881,  p.  45  ;  P.  B.-A.,  No.  18.    Filaments  deep  green,  attached 
by  outgrowths  from  within  the  lower  cells,  30-60  p.  diam.,  cells 
YZ-Z  diam.  long,  usually  ^-1^2;  vegetative   cells  cylindrical, 
fertile  cells  more  or  less  swollen  ;  chromatophore  dense,  nearly 
uniform.     Fig.  133.     Greenland  to  N.  J.  ;  Alaska  to  Cal. 

Europe. 

A  common  species  of  northern  regions  on  both  sides  of  the 
continent,  growing  on  rocks  and  timber  in  exposed  places,  often 
in  company  with  Bangia  fusco-purpurca ,  and  most  abundant  in 
spring  and  summer. 

2.  H.    WORMSKJOLDII    (Mert.)   Fries,   1835,  p.   328;    Hor- 
motrichum   (?)    Wormskjoldii    Harvey,    1858,    p.    91  ;     Urospora 
Wormskjoldii  Rosenvinge,  1893,  p.  920,  fig.  36;  P.  B.-A.,  No. 
915.     Filaments    attached   by  fibrils  proceeding   from  the  cell 
wall,  30-60  p.  diam.  at  the  base,  increasing  in  size  upward,  even 
to  500 /u,;  lower  cells  cylindrical,  3-10  diam.  long,   upper  cells 
shorter,  fertile  cells  swollen,  the  largest  nearly  globular ;  chro- 
matophore an  open  network.     Greenland  ;  Alaska  to  Wash. 


THE  GREEN  ALGAE  OF  NORTH  AMKKICA  369 

A  northern  species,  distinguished  by  the  great  difference  in 
size  between  the  base  and  summit  of  filament ;  the  lower  cells 
cylindrical,  several  times  longer  than  broad  ;  the  upper  cells 
ovoid  or  globular. 

3.  H.  Hartzii  (Rosenv.)  nov.  comb.  ;    Urospom  If.u-tzii  Ros- 
envinge,    1893,    p.   922,    fig.   38.      Filaments  75-90  /*  thick,  of 
nearly  uniform  diam.,  cells  ^-3  diam.  long,  usually  1-2,  cylin- 
drical or  very  slightly  swollen,  fertile  similar  to  vegetative  ;  'cell 
wall  thin  ;  chromatophore  an  open  network.     Greenland. 

This  species  has  only  been  found  unattached  ;  the  manner  of 
attachment,  if  known,  would  indicate  whether  it  was  allied  in 
this  respect  with  H.  penicilliformis  or  with  H.  Worniskjoldii.  Jin 
the  uniform  diameter  of  the  filaments  it  agrees  with  the  former, 
but  has  larger  and  usually  longer  cells,  with  thinner  walls  ;  in 
the  arrangement  of  the  chromatophore  it  agrees  with  the  latter. 

4.  H.  crassa  (Rosenv.)  nov.  comb.  ;    Urospora  crassa  Rosen- 
vinge,  1898,  p.  106,  fig.  23.     Filaments  tapering  to  the  base  and 
somewhat  to  the  apex  ;  lower  cells  up  to  70  /A,  middle  part  120- 
150,  summit  105  /A  diam.  ;  cells  in  smaller  portion  >^  diam.  long, 
nearly  cylindrical;  in  larger  portion  YI-I/\  diam.  long,  swollen  ; 
cell  wall  thick,  chromatophore  a  network  with  relatively  small 
openings.     Greenland. 

An  imperfectly  known  species,  neither  the  base  of  the  fila- 
ment nor  the  fertile  cells  having  been  observed  ;  its  best  charac- 
ter would  seem  to  be  the  short  and  stout  cells. 

5.  H.  incrassata  (Kjellm.)  nov.  comb.  ;    Urospora  incrassata 
Kjellman,    18973,   p.   7,   figs.  6-13;  P.  B.-A.,  No.  1125.     Fila- 
ments attached  by  fibrils  from  the  cell  wall  at  the  base,  about 
45  p.  diam.  at  the  base,  increasing  to  135  /*,  somewhat  diminish- 
ing in  the  few  cells  at  the  apex;   lower  cells  cylindrical,  1-4 
diam.   long;  upper  cells  i-i}£   diam.   long,  swollen;    cell  wall 
rather  thin,  chromatophore  an  open  network.     Alaska  to  Cal. 

Europe. 

Nearly  related  to  H.  Wormskjoldii  and  H.  crassa  ;  the  former 
has  a  greater  difference  in  size  between  base  and  apex,  and  both 
have  thicker  cell  wall  and  shorter  cells. 

6  H.  COLLABENS  (Ag.)  Rabenhorst,  1868,  p.  364  ;  Conferva 
collabcns  Harvey,  1846-51,  PL  CCCXXVII ;  Ulothrix  collabens 
Farlow,  1881,  p.  45  ;  P.  B.-A.,  No.  970-  Filaments  very  soft 
and  lubricous,  bright  green,  attached  by  growths  from  within 
the  lower  cells,  cylindrical  or  increasing  slightly  upwards,  vary- 
ing much  in  diameter,  50-170 /x;  cells  1-3  diam.  long,  usually 


370          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

somewhat  swollen,  fertile  much  swollen  ;  cell  wall  rather  thin, 
chromatophore  a  rather  close  network.     Mass.  Europe. 

The  soft,  lubricous  substance  is  characteristic  of  this  species, 
also  the  great  variety  in  diameter  of  filaments  growing  in  the 
same  tuft.  It  is  found  on  exposed  rocky  shores,  in  the  lower 
litoral  region,  in  very  early  spring. 

Family  2.     GOMONTIACEAE. 

Fronds  consisting  of  creeping,  branched  filaments  ;  cells  multi- 
nucleate  ;  asexual  reproduction  by  biciliate  zoospores  or  by 
aplanospores,  both  produced  in  sporangia  formed  on  the  upper 
surface  of  the  horizontal  layer,  and  ultimately  detached  from 
the  same.  Only  one  genus. 

GOMONTIA  Bornet  and  Flahault,  1888,  p.  163. 
Characters  of  the  family. 

KEY  TO  THE  SPECIES  OF  GOMONTIA. 

i.     In  marine  shells  ;  filaments  4-8  /*  diam.  i.     G.  polyrhiza. 

i.     In  fresh-water  shells  ;  filaments  12-50 /x  diam.          2.     G.  Holdenii. 

i.  G.  POLYRHIZA  (Lagerh.)  Bornet  and  Flahault,  1888,  p. 
164;  1889,  p.  CI/VIII,  PI.  VI,  VII;  P.  B.-A.,  No.  315.  Fila- 
ments 4-8  p.  diam.  ;  sporangia  30-40  /A  diam.;  zoospores  of  two 
sorts,  one  10-12X5-6  yu.,  the  other  about  5X3.5  p\  development 
not  known  ;  aplanospores  4  ^  diam.  Fig.  135. 

Abundant  everywhere  in  dead  shells  on  the  shore ;  the  fila- 
ments penetrating  the  substance  of  the  shell,  branching  much 
and  irregularly  ;  sometimes  forming  a  dense  network  for  a  con- 
siderable distance.  It  seldom  occurs  quite  pure,  but  is  usually 
in  company  with  Mastigocolcus  testarum  L,agerh.  and  Hyella 
caespitosa  B.  and  Fl.  The  three  species  show  as  stains  on  the 
surface  of  the  shell,  each  having  its  own  special  color ;  the 
Gomontia,  grass-green  ;  the  Mastigocoleus  blaish-  or  violet-gray ; 
the  Hyella  grayish-  or  yellowish-green.  The  latter,  however, 
seldom  occurs  in  sufficient  quantity  or  purity  to  give  its  own 
color  to  the  shell.  In  studying  these  species  the  calcareous 
matter  must  be  dissolved  away  ;  Perenyi's  fluid  seems  to  be  the 
best  agent. 

G.  polyrhiza  probably  occurs  all  along  both  coasts ;  besides 
inhabiting  dead  shells,  it  is  found  on  barnacles,  and  on  the 
Spirorbis  shells  attached  to  Fuci,  etc. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  371 

2.  G.  HOLDENII  Collins,  1897,  P-  95,  PI-  IV. B.,  figs.  1-3; 
P.  B.-A.,  No.  316.  Filaments  12-50 /«.  diam.,  cells  irregular  in 
shape,  oval,  cylindrical  or  polygonal,  terminal  cell  cylindrical 
or  tapering  ;  sporangia  ovoid  with  elongate  base,  100X30 p..  In 
Unio  shells,  in  fresh  water.  Conn. 

The  large  irregular  cells  distinguish  this  from  G.polyrhiza. 

Family  3.     VALONIACEAE. 

Frond  originating  in  a  vesicular  or  clavate  cell  of  limited 
growth,  in  all  but  the  lowest  forms  branching  or  dividing  into 
many  cells,  which  may  be  irregularly  arranged,  or  may  form 
symmetrical,  sometimes  netlike  fronds.  Intercalary  cell  divi- 
sion by  ordinary  wall  formation  is  not  common  ;  new  cells  arise 
generally  by  an  outgrowth  from  the  parent  in  a  way  that  leaves 
some  doubt  as  to  whether  the  new  cell  should  not  be  considered 
as  a  new  individual,  or  else  by  the  closing  in  of  annular  con- 
strictions of  the  frond.  All  marine,  chiefly  plants  of  warmer 
waters. 

Oltmanns,  1904,  p.  255,  removes  from  this  family  the  genera 
Stphonocladus,  Chamacdoris  and  Struvea,  to  form  the  family 
Siphonocladiaceae.  The  main  distinction  seems  to  be  the  pres- 
ence of  a  distinct  axis  in  the  latter.  If  we  follow  Borgesen, 
1905,  p.  288,  and  remove  from  Siphonocladus  S,  membranaccns 
and  its  allies,  this  genus  and  the  remaining  genera  of  the  family 
agree  in  the  presence  of  an  original  upright  cell  of  limited 
growth,  and  in  the  absence  or  rarity  of  intercalary  division  of 
the  cells  by  cross  walls ;  there  would  seem  to  be  no  need  of 
dividing  the  family. 

KEY  TO  THE  GENERA  OF  VALONIACEAE. 

i.     Frond  always  unicellular.  i.     HAIJCYSTIS. 

r.     Mature  frond  pluricellular.  2. 

2.     Original  cell  constituting  a  stipe  different  in  character  from  the 

rest  of  the  frond.  3- 

2.     All  cells  similar  to  the  original.  4. 

3.     Stipe  crowned  by  a  network.  6.     STRUVEA. 

3.     Stipe  crowned  by  a  dense  tuft  of  filaments.          5.     CHAMAEDORIS. 

4.     Daughter  cells  arising  from  the  surface  of  the  mother  cells. 

2.    VALONIA. 
4.     Entire  contents  of  cell  dividing  into  numerous  smaller  cells,  each 

of  which  may  develop  like  the  mother  cell.  5. 

5.     Erect  or  tufted,  not  calcified.  3.     SIPHONOCLADUS. 

5.     Forming  an  adherent  disk  ;  somewhat  calcified. 

4.    PETROSIPHON. 


372  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

i.     HALICYSTIS  Areschoug,  1850,  p.  447. 

Frond  unicellular",  multinucleate,  saccate,  with  narrow  basal 
portion;  chromatophores  minute  disks  without  pyrenoid. 
Asexual  reproduction  by  biciliate  zoospores  without  stigma,  es- 
caping through  one  or  more  openings ;  similar  but  smaller 
zoogametes  (?)  formed  in  separate  individuals  ;  after  the  emis- 
sion of  the  spores  the  openings  close  and  several  new  genera- 
tions of  spores  can  be  similarly  produced. 

Though  this  genus  was  proposed  for  the  following  species  as 
long  ago  as  1850,  its  validity  has  been  questioned,  but  studies 
by  Kuckuck,  1907,  remove  all  doubt. 

H.  OVALIS  (L,yng.)  Areschoug,  1850,  p.  447  ;'  Kuckuck,  1907, 
p.  139,  PL  III.  Fronds  solitary  or  gregarious,  obovate-ovoid, 
^-i  cm.  high,  about  half  as  wide ;  membrane  tough,  10-12  p. 
thick ;  basal  prolongation  penetrating  the  substratum ;  zoo- 
spores  12-14X7-8  /«.;  gametes  (?)  7-8X2-3  /*.  Fig.  130.  Van- 
couver Island  to  Monterey,  Cal.  Northern  Europe. 

This  species  has  always  been  found  growing  on  crusts  of 
Lithothamnion  or  similar  calcareous  algae,  the  radical  portion 
boring  deeply  into  the  substratum,  apparently  like  Gomontia. 

2.     VALONIA  Ginnani,  1757,  p.  38. 

Fronds  not  calcified,  at  first  a  single  ovoid  or  clavate  multi- 
nucleate  cell,  producing  more  or  less  numerous  cells  similar  in 
form  to  itself ;  this  process  being  repeated  more  or  less  fre- 
quently in  different  species;  unicellular  rhizoids  being  similarly 
produced ;  chromatophore  forming  a  network  with  many  pyre- 
noids  ;  asexual  reproduction  by  2-  or  4-ciliate  zoospores,  escap- 
ing through  numerous  openings,  and  developing  at  once  into 
plants  similar  to  the  parent. 

As  long  as  V.  ovalis  was  included  in  this  genus,  it  was  diffi- 
cult to  define  the  latter  clearly  ;  by  the  removal  of  that  species 
as  Halicystis  ovalis,  the  matter  is  much  simplified. 

KEY  TO  THE  SPECIES  OF  VALONIA. 

i.     Frond  bullate,  unbranched.  i.     V.  ventricosa. 

i.     Frond  more  or  less  abundantly  branched.  2. 

2.     Cells  obovate-clavate,  sparingly  and  irregularly  branched. 

2.      V,  utricularis. 

2.     Cells  subcylindrical.  3. 

3.     Branches  irregularly  placed.  3.      V.  aegagropila. 

3.     Branches  in  regular  whorls.  4. 

4.     Whorls  frequent  and  dense  ;  cells  rather  short. 

4.     V.  verticillata. 
4.     Whorls  distant  and  loose,  cells  long.  5.     V.  confervoides. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  373 

1.  V.  VENTRICOSA  J.   G.    Agardh,    1886,   p.    96;    Murray, 
1893,  PI.  XIII,  figs.  6-10  ;  Vickers  1908,  p.    21,   PI.  XXIII. A. 
Frond  .solitary,  saccate,  spherical  to  pyriform,  usually  2-3,  rarely 
5  cm.  diam.  ;  secondary  cells  formed  chiefly  at  the  base  for  pur- 
poses of  attachment  ;  membrane  smooth,  translucent,  showing 
the  light  green  contents.     W.  I. 

Practically  unmistakable  for  any  other  species ;  Ha/icvstis 
ova/is,  the  only  one  that  it  resembles,  being  smaller  and  an  in- 
habitant of  quite  different  regions.  The  fronds  are  usually 
about  the  size  of  a  large  cherry,  but  Murray  has  dredged 
specimens  "  as  large  as  a  hen's  egg." 

2.  V.  UTRICULARIS  Agardh,   1822,  p.  431  ;  Kutzing,  1856, 
PI.    LXXXVI,    fig.    2b-e;  Wittr.  and  Nordst.,    Alg.  Exsicc., 
No.  953.     Cells  stout,  cylindric-clavate,  with  similar  prolifera- 
tions ;  lower  parts  of  frond  decumbent,  or  creeping  among  other 
algae,  then  erect,  up  to  5  cm.  high,  often  forming  dense  tufts  ; 
membrane  dark  green,  shining;  zoospores  biciliate.     Fig.  138. 
Bermuda,  Bahama.  /Europe. 

Growing  from  the  literal  zone  to  a  depth  of  2m.;  in  the 
former  station  the  filaments  are  shorter  and  stouter  ;  in  the  lat- 
ter longer  and  more  slender. 

3.  V.  AEGAGROPILA  Agardh,  1822,  p.  429;    Kiitzing,  1856, 
PI.  LXXXVII,  fig.  i  ;  P.  B.-A.,  No.  772.     Fronds  much  and 
irregularly  branched,  cells  subcylindrical,  rather  short,  2-3  mm. 
diam.,  forming  a  dense,  globular  tuft;  membrane  rather  dull. 

-  W.  I.  Mediterranean,  Indian,  Pacific  Oceans. 

Nearly  allied  to  V.  utricularis,  but  with  more  slender,  less 
clavate  cells,  and  forming  denser  masses,  soon  freed  from  the 
substratum  and  floating  in  shallow 'water. 

4  V.  VERTICILLATA  Kiitzing,  1849,  p.  508  ;  1856,  p.  30,  PI. 
LXXXVIII;  Vickers,  1908,  p.  21,  PI.  XXIII. B;  P.  B.-A., 
No.  1533.  Cells  cylindrical,  straight,  2-3  mm.  diam.,  producing 
whorls  of  similar  cells  below  the  obtuse  apex  ;  branching  re- 
peated, forming  tufts  about  5  cm.  high;  membrane  very  deli- 
cate and  translucent.  W.I. 

The  regular  and  frequent  whorled  branches  distinguish  .this 
from  all  our  other  species;  dried  specimens  adhere  to  paper 
more  firmly  than  in  other  species. 

s  V  CONFERVOIDES  Harvey,  Alg.  Ceylon  Exsicc.,  No. 
7V  Wittr.  and  Nordst.,  Alg.  Exsicc.,  No.  349.  Fronds  decum- 
bent at  first,  then  ascending,  cylindrical,  2-3  mm.  diam.,  simple 
below,  above  branching  sparingly,  usually  3-4  branches  in  a 


374          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

whorl,  branches  patent,  more  or  less  incurved,  membrane  firm, 
color  dull  green,  forming  dense  tufts,  many  cm.  diam.  Ber- 
muda. Indian  and  Pacific  Oceans. 

L,ike  V.  vcrticillata  this  species  has  whorled  branches,  but  the 
whorls  are  fewer  branched  and  less  frequent ;  the  cells  are 
many  times  longer. 

3.  SIPHONOCLADUS  Schmitz,  1878,  p.  17. 
Frond  originating  in  a  simple  clavate  cell,  attached  by  multi- 
cellular  rhizoids  at  the  base,  of  definite  growth  ;  ultimately  be- 
coming multicellular  by  the  transformation  of  the  contents  into 
cyst-like  cells,  uniting  sub-parenchymatously,  then  each  push- 
ing through  the  mother  cell  wall,  assuming  a  shape  like  the 
mother  cell  and  developing  in  the  same  way  as  the  latter. 
Asexual  reproduction  by  escape  and  growth  of  the  cysts  ;  re- 
production also  by  zoospores  formed  in  large  numbers  in  the 
clavate  cells ;  probably  asexual.  Ordinary  cell  division  by 
cross  walls  not  certainly  observed. 

The  primary  cell  in  Valonia  appears  to  bear  branches  with  a 
partition  at  the  base  of  each ;  in  Siphonodadus  a  multicellular 
filament  appears  to  take  the  place  of  the  primary  cell,  each  cell 
of  the  filament  producing  a  branch  without  partition  at  the  base. 

KEY  TO  THE  SPECIES  OF  SIPHONOCLADUS. 

i.     Primary  cell  long,  erect ;  substance  soft.  i.     S.  tropicus. 

i.     Primary  cell  short ;  substance  firm  and  crisp.  2.     S.  rigidus. 

1.  S.    TROPICUS    (Crouan)    J.    G.    Agardh,    1886,    p.    105; 
Howe,  1905,  p.  245,  PI.  XIII,  fig.  2  ;  Vickers,  1908,  p.  20,  PI. 
XVIII.     Primary  cell   up   to  4   cm.  long,    i   cm.   wide,   with 
annular  constrictions  near  the  base  ;  branches  similar,  also  with 
constrictions  near   base,   often   longer  than   the  primary   cell ; 
cells  of  third  generation  similar  but  generally  shorter  ;  zoospores 
many  in  a  cell  which  has  reached  its  full  growth,  escaping  by 
small  perforations  in  the  walls.     Fla.,  W.  I. 

2.  S.  RIGIDUS  Howe,  1905,  p.  244,  PI.  XII,  fig.  i  ;  PI.  XIV  ; 
P.  B.-A.,   No.  1489;  6".  tropicus  P.  B.-A.,  No.   1031.     Frond  a 
more  or  less  dense  tuft  of  pale  green,  crisp  filaments,  main  axis 
hardly  distinguishable  ;   branching  sub-dichotomous,  irregular, 
or  secund  ;    filaments  350-1100  /j.  diam.,  often  united  by  short 
tenacula.     Fig.  139.     Bahama. 

Howe's  description  of  this  species  was  apparently  written 
without  knowledge  of  Borgesen,  1905,  which  was  published 
about  the  same  time ;  in  the  light  of  Borgesen's  studies  of  S. 


THK  GREEN  AI.GAE  OF  NORTH  AMERICA  375 

t>-of>ints,  Howe's  figures  of  S.  rigidus  would  seem  to  be  inter- 
preted best  as  representing  a  development  by  "cysts,"  much 
as  in  the  former  species.  There  is  little  doubt  of  the  distinct- 
ness from  S.  tropicns,  but  the  relations  in  this  direction  are  cer- 
tainly closer  than  those  with  Cladophoropsis  incnibntncuriis. 
It  is  at  least  probable  that  the  lateral  branches  in  Howe,  PI. 
XI V,  fig.  2,  correspond  to  the  branches  in  Borgesen,  fig.  4  ;  and 
that  the  frond  originates  in  a  similar,  somewhat  clavate  cell. 

4.     PETROSIPHON  Howe,  1905,  p.  248. 

Filaments  united  to  form  a  disk,  somewhat  calcified,  firmly 
attached  to  the  substratum,  and  piercing  the  same  by  rhizoids  ; 
disk  monostromatic  at  the  margin,  polystromatic  elsewhere,  the 
center  often  of  short,  erect  filaments ;  asexual  reproduction  by 
aplanospores. 

P.  ADHAERENS  Howe,  1905,  p.  248,  PI.  XV.  Disks  light 
green,  2-6  cm.  diam.,  orbicular  or  irregular,  closely  approxi- 
mate ;  margin  striate  ;  up  to  5  mm.  thick  at  the  center ;  hori- 
zontal filaments  300-850  \t.  diam.,  straight  or  geniculate,  dichoto- 
mous  ;  cells  ^2-20  diam.  long  ;  rhizoids  very  abundant,  pene- 
trating the  substratum  ;  aplanospores  varying  in  size  and  form. 
Bahamas. 

In  characters  of  filaments,  etc.,  like  Siphonodadus ,  but  differ- 
ing by  the  definite  disk-shaped  frond,  and  the  incrustation  ;  it 
is  closely  adherent  to  the  rock  on  which  it  grows. 

5.     CHAMAEDORIS  Montague,  1842,  p.  261 
Frond  erect,  with  firm,  clavate  stipe,  attached  by  rhizoids  at 
the  base,  and  bearing  a  dense  tuft  of  branching,  articulate  fila- 
ments at  the  tip  ;  stipe  monosiphonous,  with  closely  set,  annular 
constrictions,  much  calcified. 

C.  ANNUL  ATA '( Lamarck)  Montagne,  1842,  p.  261  ;  Harvey, 
1858,  p.  43,  PI.  XLII.B;  Vickers,  1908,  p.  22,  PL  XXIV;  P. 
B.-A.,  No.  629  The  only  species ;  stipe  up  to  10  cm.  high; 
head  2-3  cm.  diam.  Fig.  136.  Fla.,  W.  I. 

Africa,  So.  America,  Indian  Ocean. 

The  mop-shaped  fronds  are  not  to  be  mistaken. 

6.     STRUVEA  Sender,  1845,  p.  49. 

Frond  attached  below  by  multicellular  branched  rhizoids ; 
stipe  simple  or  branched,  monosiphonous,  bearing  one  or  more 
flabelliform,  net-like  expansions,  consisting  of  articulate,  pin- 
nately  branched  filaments,  the  tips  of  the  branches  attaching 


376          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

themselves  to  other  filaments  to  form  the  network.     Reproduc- 
tion unknown. 

A  genus  of  tropical  algae,  with  beautifully  symmetrical  net- 
like  fronds,  in  which  the  filaments  apparently  anastomose,  but 
really  are  united  by  peculiar  organs,  "tenacula,"  formed  on  the 
tips  of  the  cells  when  they  come  in  contact  with  other  cells  of 
the  fronds,  or,  in  some  species,  of  other  fronds.  The  tenacula 
are  short  cylindrical  prolongations  of  the  cell  wall,  ending  in 
dense  short  branches  ;  reminding  one  somewhat  of  the  shape  of 
a  sea-anemone.  In  the  corresponding  organs  in  Microdictyon 
the  attaching  surface  has  a  somewhat  crenulate  margin,  but 
does  not  develop  branches.  The  primary  cell  of  Struvca  is  at 
first  clavate,  later  spindle-shaped,  and  appears  to  attain  its  full 
growth  before  the  network  is  formed.  There  is  some  uncer- 
tainty as  to  how  the  "  articulations  "  of  the  network  arise,  but 
it  seems  probable  that  it  is  by  the  deepening  of  the  annular  con- 
strictions, not  by  true  wall  formation. 

KEY  TO  THE  SPECIES  OF  STRUVEA. 

i.     Stipe  unbranched.  i.     S.  anastomosans. 

i.     Stipe  branched.  2. 

2.     Each  branch  of  the  stipe  with  a  separate  network. 

3.     5".  ramosa. 
2.     One  network  only.  2.     S.  pulcherrima. 

i.  S.  ANASTOMOSANS  (Harv.)  Piccone,  1884,  p.  20;  S.  deli- 
catula  Murray  and  Boodle,  1888,  p.  281,  PL  XVI,  figs.  6  and  8  ; 
Vickers,  1908,  p.  20,  PI.  XIX  ;  Cladophora  anastomosans  Harvey, 
1855,  p.  565,  name  only;  1859,  PI.  CI.  Stipe  smooth,  simple, 
slender,  crowned  with  a  subpyramidal  network,  3-5  cm.  long  ; 
filaments  repeatedly  pinnate,  pinnae  and  pinnules  opposite, 
horizontally  patent,  more  or  less  attached  to  each  other. 
Fig.  134.  Guadeloupe,  Jamaica.  Australia,  Canaries. 

This  species  shows  a  resemblance  to  the  Pcllucida,  section  of 
Cladophora;  the  union  of  the  branches  is  only  partial,  and 
varies  much  as  to  completeness. 

Var.  CARACASANA  Grunow  in  Murray  and  Boodle,  1888,  p. 
281  ;  Vickers,  1908,  p.  20,  PI.  XX.  Frond  regularly  bipinnate  ; 
branches  seldom  united.  Barbados.  So.  America. 

2.  S.  PULCHERRIMA  (J.  E.  Gray)  Murray  and  Boodle,  1888, 
p.  281,  PI.  XVI,  fig.  4.  Stipe  smooth,  three-parted,  crowned 
with  a  single,  cordate,  three- ribbed  network,  30X20  cm.  ;  fila- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  377 

merits  repeatedly  pinnate,  articulations  of  the  pinnae  3-4  diam. 
long,  of  the  pinnules  2  diam.     Fla.,  Gulf  of  Mexico. 

This  species  was  dredged  by  Menzies  early  in  the  last  cent- 
ury, and  his  single  specimen  remained  undescribed  until  1866, 
when  it  was  taken  by  J.  E.  Gray,  1866,  p.  70,  as  the  type  of  the 
new  genus  Wiyllodictyon.  The  original  specimen,  though  over 
30  cm.  long,  is  evidently  fragmentary  ;  a  single,  smaller  frag- 
ment, found  by  Mrs.  G.  A.  Hall,  at  Jupiter  Inlet,  Florida,  is 
the  only  record  since  Menzies.  5".  pulcherrima  seems  to  be  the 
rarest,  as  well  as  one  of  the  most  interesting  of  our  green 
algae. 

3.  S.  RAMOSA  Dickie,    1874,   p.   316;    Murray  and  Boodle, 
1888,  p.  280,  PI.  XVI,  fig.  3.     Stipe, with  a  few  annular  con- 
strictions, above  oppositely  branched,  each  branch  ending  in  a 
sub-elliptical  network,  about  3X1^  cm.;  filaments  tripinnate, 
lower   articulations   7-8   times    their   diam.,   upper   3-4   times. 
Bermuda. 

Family  4.     DASYCLADACEAE. 

Frond  consisting  of  a  long,  inarticulate  axillary  cell,  attached 
by  rhizoids  below,  and  of  whorls  of  usually  pluricellular,  simple 
or  branching  ramuli  of  limited  growth  ;  in  fertile  ramuli  are 
produced  either  gametes,  or  aplanospores  which  when  freed 
produce  gametes. 

Marine  plants  of  warm  waters  and  general  distribution. 

•     KEY  TO  THE  GENERA  OF  DASYCLADACEAE. 

i.     Frond  calcified.  2. 

i.     Frond  not  calcified.  6. 

2.     Frond  with  slender  stipe  and  with  whorls  of  branches  terminal 

or  at  considerable  intervals.  3- 

2.     Whorls  of  branches  contiguous,  concealing  the  axis.  5. 

3.     Spores  contained  in  whorled  branches,  not  calcified. 

I.      ACETABULARIA. 

3.     Spores  contained  in  whorled  branches,  calcified.  4- 

4.  Spores  imbedded  in  a  solid  mass  of  lime,  but  membrane  free  from 

lime.  3-     ACICULARIA. 

4.     Spores  free,  membrane  much  incrusted.  2.     CHALMASIA. 

5.     Stem  branching,  moniliform.  5-     CYMOPOLJA. 

5.     Stem  unbranched,  surface  continuous.  4-     NEOMERTS. 

6.     Sporangia  terminal ;  whorls  very  closely  set.     6.     DASYCLADVS. 

6.     Sporangia  lateral,  whorls  rather  distant.  7.     BATOPHORA. 

i.     ACETABUI.ARIA  Lamouroux,  1816,  p.  244. 
Frond  calcified,  with  perennial  root  and  annual  erect  axis 


378  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

clothed  with  deciduous  whorls  of  hairs,  terminating  in  a  cap- 
like  whorl,  with  rays  either  free  or  joined ;  each  ray  bearing  on 
its  upper  surface  near  the  base  a  prominence,  the  prominences 
forming  a  ring  "  corona  superior,"  with  scars  corresponding  to 
deciduous  tufts  of  hairs  borne  by  them.  A  corresponding  ring 
on  the  lower  surface  of  the  rays  "  corona  inferior  "  is  present  in 
some  species.  Entire  contents  of  the  rays  changing  into  glo- 
bose Or  ovoid  aplanospores  with  membrane  free  from  lime  ;  after 
a  period  of  rest  these  aplanospores  open  by  a  cap,  and  give  out 
zoogametes,  which  by  conjugation  form  a  zygote,  by  wrhose 
germination  the  plant  is  reproduced. 

A  genus  of  very  delicate  and  beautiful  plants,  seldom  over  a 
few  cm.  high,  living  in  shallow  salt  water  in  tropical  and  sub- 
tropical regions.  The  two  following  genera,  Chalmasia  and 
Acicularia,  are  practically  of  the  same  habit,  but  differ  in  spore 

characters. 

KEY  TO  THE  SPECIES  ov  ACETABULARIA. 

i.     Rays  less  thati  20.  2. 

i.     Rays  20  or  more.  3. 

2.     Corona  superior  not  over  35  fj.  diam.  5.     A.  pnsilla. 

2.     Corona  superior  75  M  diam.  or  more.  4.     A.  polyphysoides. 

3.     Rays  apiculate.  i.     A.  crenulata. 

3.     Rays  not  apiculate.  4. 

4.     Rays  free  or  slightly  coherent.  3.     A.  Farlowii. 

4.     Rays  firmly  united.  2.     A.  caliculus. 

1.  A.  CRENULATA  L,amouroux,  1816,  p.  249;  Harvey,  1858, 
p.    40,    PI.    XLII.A.  ;    Viokers,    1908,    p.    29,    P1..XLVIII; 
P.  B.-A.,    No.    125;    A,   caraibica   Kiitzing,    1856,    p.    33,    PI. 
XCIII ;  Vickers,    1908,  p.  29,    PL  XLJX.     Stipe  up  to  4  cm. 
high,  bearing  a  terminal  disk  with  crenulate  margin,  6-15  mm. 
diam.,  and  often  several  other  disks  at  various  points,  or  nodes 
showing  the  positions  of  former  disks ;  rays  (sporangia)  30-80, 
firmly  united,  ends  arched,  with  a  short  apiculum  at  the  middle  ; 
corona  superior  .15-. 26  mm.  diam.,  with  two  hair-scars  on  each 
ray;    aplanospores  75-140  //,  diam.,  300-500  in  a   sporangium. 
Fig.  131.     Fla.,  W.  I. 

A  common  and  beautiful  species,  in  general  shape  like  a 
small  and  delicate  mushroom.  A.  caraibica  is  kept  distinct  by 
Solms,  1895,  but  Howe,  1901,  having  made  a  careful  study  of 
the  living  plants  of  our  American  species,  finds  it  impossible  to 
distinguish  the  two. 

2.  A.  CALICULUS  Quoy  and  Gaimard,  1824,  p.  621,  PL  XC, 
figs.  6  and  7;  Solms,    1895,   p.   25;  A.  Suhrii  Solms,  1895,  P- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  379 

25,  PI.  I,  figs.  9  and  13.  Slender,  stipe  1^-3  cm.  high,  with 
occasional  spindle-shaped  swellings;  disk  cup-shaped,  6-7  p. 
diam.  ;  rays  25-30,  not  strongly  united,  the  blunt  margin  with  a 
broad,  deep,  squarish  depression  ;  corona  superior  about  90  n 
diam.,  with  2  or  3,  sometimes  4  hair-scars  on  each  ray  ;  aplano- 
spores  about  160 /u.  diam.,  about  80  in  a  sporangium;  gametes 
developed  before  the  release  of  the  aplanospores  from  the 
sporangium.  St.  Thomas,  Jamaica. 

Indian  and  South  Pacific  Oceans. 

In  general  appearance  like  a  delicate  A.  crenulata,  but  with 
only  one  disk,  different  shape  in  the  margin  of  the  disk,  usually 
more  hair-scars  than  in  A.  crenulata,  and  with  rays  less  firmly 
united. 

3.  A.  FARI.OWII  Solms,  1895,  p.  27,  PI.  Ill,  fig.  i  ;  P.  B.-A., 
No.  1032;  Acetabulum  Farlowii  Howe,  19053^.577.     Stipe  1-2 
cm.  high;  disk  4-7  mm.  diam.,  nearly  flat;  rays  20-30,  lightly 
coherent  or  free,   slightly  compressed  towards   the   obtuse   or 
truncate  ends  ;  corona  superior  .15  mm.   diam.,  with  two  hair- 
scars  on  each  ray  ;  aplanospores  40-120  in  a  sporangium.     Fla. 

Distinguished  from  A.  crenulata  by  the  loosely  attached  or 
entirely  free  rays,  and  from  A.  caliadus  by  the  flattish  disk  with 
obtuse  rays;  in  mature  plants  the  rays  are  often  entangled,  so 
that  the  regular  form  of  the  disk  is  lost. 

4.  A.  POLYPHYSOIDES  Crouan  in  Schramm  and  Maze,  1866, 
p.    101  ;  Solms,    1895,   P-  29>   P1-   IV,   figs.  2  and  6;  Vickers, 
1908,  p.  28,  PI.  XLVII ;  Acetabulum  polyphysoides  Howe,  1909, 
p.  92,  PL  VI,  figs.  16-20;  PI.  VII,  figs.  5-9.     Stipe  seldom  over 
i   cm.   high,   disk    single,  cup-shaped  or  nearly  flat,   2-5   mm. 
diam.  ;  rays  11-25,  mostly  12-18,  vesicular,  from  obovoid  to  sub- 
fusiform,  obtuse  and  rounded  at  the  end,   loosely  united  -by  a 
thin  calcification;  corona  superior  75-150/1  diam.,   a  whorl  of 
5-13,  usually  8  or  9,  hair-scars  on  each  ray  ;  aplanospores  90- 
190  p.  diam.,  6-50  in  a  sporangium.     W.  I. 

The  few  and  swollen  rays  sufficiently  distinguish  this  species 
from  the  preceding,  apart  from  the  characters  of  the  hair-scars. 

Forma  deltoidea  (Howe)  nov.  comb.;  Acctabnlum  polyphys- 
oides dcltoideum  Howe,  1909,  p.  92,  PI.  VI,  fig.  21  ;  PI.  VII, 
fig.  10.  Rays  usually  7,  much  inflated,  inversely  deltoid  or 
obovoid-deltoid  ;  hairs  scars  6-8.  Bahamas. 

Very  distinct  in  appearance  by  the  few  and  broad  rays,  but 
there  are  intermediate  forms  between  this  and  the  typical  form. 

5.  A.    pusilla    (Howe)    nov.    comb.;    Acetabulum   pusillum 


380          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Howe,  1909,  p.  89,  PI.  VI,  figs.  13-15;  PI.  VII,  figs.  1-4, 
Stipe  1-3  mm.  high,  disk  solitary,  nearly  flat,  1-2.5  mm-  diam., 
rays  6-17,  usually  11-15,  obovoid-clavate  to  clavate-subfusiform, 
blunt  or  obtusely  taper-pointed,  easily  separable  ;  corona  supe- 
rior 22-35  /"•  diam,,  with  2,  rarely  3  hair-scars  ;  aplanospores 
15-60  in  a  sporangium,  68-82  p.  diam.  W.  I. 
The  smallest  of  our  species,  and  quite  lightly  calcified. 

2.     CHALMASIA  Solms,  1895,  p.  32. 

Disk  terminal,  composed  of  rays  united  only  by  the  incrusta- 
tion ;  corona  inferior  wanting  ;  segments  of  the  corona  superior 
not  touching  laterally  ;  aplanospores  free,  with  thick,  much  cal- 
cified membrane.  Only  one  species. 

C.  ANTILLANA  Solms,  1895,  p.  32,  PL  III,  figs.  2,  3,  5.     Disk 
funnel-shaped,   6  mm.  diam.,  rays  25-32,  covered  with  a  thin, 
easily  detachable  incrustation,  and  not  otherwise  united,  vesic- 
•  ular  and   inflated ;    aplanospores  globular,   chalk- white ;    hair- 
scars  2-3.     Fig.  140. 

In  habit  quite  like  a  small  Acetabularia  crenulata,  but  suffi- 
ciently distinct  in  the  spore  characters.  The  only  known  speci- 
mens were  dredged  at  some  point,  not  definitely  known,  off  the 
Florida  coast. 

3.  ACICULARIA  D'Archiac,  1843,  p.  386. 

Rays  of  the  disk  united,  corona  superior  and  corona  inferior 
present ;  interior  of  the  ray  ultimately  occupied  by  a  calcareous 
mass  enclosing  uncalcified  aplanospores. 

The  genus  was  founded  by  the  paleontologist  D'Archiac  in 
1843,  on  certain  minute  spicules  found  in  the  Eocene  formation 
in  France ;  two  or  three  other  fossil  species  have  since  been 
recognized,  but  only  one  living  species  is  known. 

A.  SCHENCKII  (Mob.)  Solms,  1895,  p.  33,  PI.  Ill,  figs.  4,  9, 
n,  12,  14,  15.  Stipe  1-3  cm.  high,  thin-walled,  rather  stout; 
disk  6  mm.  diam.,  flat  or  nearly  so,  with  crenulate  margin  ; 
rays  30-50,  fairly  closely  united,  wedge-shaped  ;  corona  superior 
13  mm.  diam.,  with  2  hair-scars  to  each  ray;  aplanospores 
100-200  in  a  ray,  globose,  60-80  p.  diam.  From  literal  to  30  in. 
depth.  Bermuda,  Martinique,  Guadeloupe.  So.  America. 

4.  NEOMERIS  L,amouroux,  1816,  p.  241. 

Frond  cylindric-clavate,  more  or  less  strongly  calcified,  con- 
sisting of  a  simple,  inarticulate  axis,  attached  by  lobed  or 
branched  holdfasts,  and  bearing  thickly  set,  uniform  whorls  of 
12-80  primary  branches,  each  branch  except  those  of  the  lower 
whorls  bearing  a  terminal  short-stiped  sporangium,  and  two 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  381 

secondary  branches,  whose  swollen  tips  constitute  the  surface  of 
the  frond,  and  which  when  young  bear  each  a  simple  or  branch- 
ing hair  ;  sporangium  containing  a  single  large  spore,  probably 
an  aplanospore,  with  an  operculum  at  the  base  ;  development 
unknown. 

Rather  insignificant  appearing  plants,  the  species  much  alike 
in  habit,  demanding  dissection  and  microscopic  examination  for 
specific  determination.  Howe,  1909,  gives  full  details  of  foreign 
as  well  as  of  American  species. 

KKY  TO  THE  SPECIES  OF  NEOMERIS. 

i.     Branches  of  the  second  order  subfusiforrn,  hardly  forming  a  cortex. 

4.     N,  Cokeri. 

i.     Ends  of  the  branches  of  the  second  order  forming  a  cortex  with  dis- 
tinct facets.  2. 
2.     Sporangia  laterally  coherent  by  the  calcareous  coating. 

3.     N.  annnlata. 

2.     Sporangia  strongly  calcified  but  mutually  free.  3. 

3.     Plants  1-2  mm.  thick,  15-20  times  as  long.  i.     N.  dumetosa. 

3.     Plants  1.5-2.5  mm.  thick,  4-8  times  as  long.  2.     N.  mucosa. 

1.  N.  DUMETOSA  L,amouroux,  1816,  p.  243,  PI.  VII,  fig.  8; 
Howe,  1909,  p.  77,  PI.  I,  fig.  i  ;  PI.  V,  fig.  20;  PI.  VI,  figs,  i 
and  2.     Gregarious  or  scattered,  subcylindrical,  slender,  20-40 
mm.  high,  1-2  mm.  thick,  apex  acute  or  acuminate;   primary 
branches  500-700  /u.  long,  14-30  //-  diam.,  28-40  in  a  whorl,  whorls 
300-400,  averaging  100  /*  apart,  more  distant  near  the  apex  ; 
secondary   branches   capitate,   inflated  at  the  tip  to   100-185^ 
diam.,    outwardly   rounded,    strongly  calcified    except   on   the 
outer  surface ;    sporangia   strongly  calcified  but  mutually  free, 
containing  each  an  aplanospore  i35-i6oX  iSQ^SS  M-     W.  I. 

Europe. 

The  original  species  of  the  genus,  and  the  one  to  which  all 
forms  were  first  referred ;  not  found  in  recent  years  in  the  West 
Indies,  very  likely  narrowly  limited  in  its  localities,  like  some 
of  the  other  species  of  the  genus. 

2.  N.  MUCOSA  Howe,   1909,  p.  84,  PI.  I,  fig.  5  ;  PI.  V,  figs. 
1-14.     Gregarious,  mostly  in  clusters  of  3-20;  subcylindrical  or 
fusiform,  8-20   mm.  high,    1.5-2.5    mm.  thick,    apex   acute   or 
acuminate;    primary  branches   275-400  p.   long,   cylindrical  or 
clavate,  mostly  40-100  /x  diam.,  28-48  in  a  whorl,  whorls  120-300, 
averaging  120  /*  apart ;  secondary  branches  capitate,  inflated  at 
the  tip  to  100-220  /u,  diam.,  strongly  calcified  except  at  the  end 
surface,   which  is  mammiform,  subconical  or  subrostrate,   with 
very  thin,  mucilaginous  wall;  sporangia  strongly  calcified  but 


382  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

mutually  free ;  aplanospores  obovoid,  140-160X105-120^.     Ba- 
hamas, Cuba. 

A  shorter  and  stouter  plant  than  N.  dumetosa,  with  very  soft 
and  gelatinous  membranes. 

3.  N.  ANNULATA  Dickie,   1874,  p.  198  ;    Howe,  1909,  p.  87, 
PL  I,  fig.  2;  N.  Kelleri  Cramer,    1888,   p.  3,   PI.  I,   fig.    2  ;   PI. 
II,  figs.   1-12;  PI.  Ill,  figs.   1-2;   1890,  p.  9,   PL  I,  figs.    1-12; 
PL  II,  figs.  1-6;   PL   IV,  figs.  15-24;   Vickers,    1908,  p.  28,  PL 
XL,VI ;  N.  dumetosa  P.  B.-A.,  ^No.  668.     Mostly  densely  gre- 
garious, subcylindrical  or  fusiform-clavate,  5-25  mm.  high,  1-2 
mm.  thick,  apex  subacute  ;  primary  branches   200-280  ^  long, 
11-20  /A  median  diam.,  20-56  in  a  whorl,  whorls  60-175,  115-250 
//.   apart ;  secondary  branches   capitate,   inflated   at   the   tip   to 
80-135  f-  diam.,  outwardly  usually  rounded,  rather  firm-walled, 
strongly  calcified    except   at    the    outer   end,    firmly  coherent ; 
sporangia  strongly  calcified   and  laterally  coherent  into  nearly 
complete    or    more    or    less   interrupted    rings ;    aplanospores 
oblong-ovoid  to  oblong-ellipsoid,   115-175X46-80  p..     Fig.  143. 
Fla.,  W.  I.  So.  America,  Indian  and  Pacific  Oceans. 

The  complete  or  somewhat  broken  rings  of  sporangia  can  gen- 
erally be  depended  on  to  distinguish  this  species. 

4.  N.  COKERI  Howe,  1904,  p.  97,  PL  VI,  figs.  3-12;   1905, 
p>  580;   1909,  p.  89,  PL  I,  fig.  6.     Solitary  or  somewhat  grega- 
rious, subcylindrical  or  clavate,  7-37  mm.  high,  1.5-3  mm.  diam., 
apex  rounded,  obtuse  or  subtruncate  ;  primary  branches  200-300 
/u,  long,  30-40  p.  diam.,  12-56  in   a  whorl,  whorls  60-175,  about 
100  /A  apart;    secondary  branches  somewhat  calcified,  scarcely 
adherent,  subfusiform,  curved  or  gibbous,  100-150  /u.  diam.  near 
the  middle,  tapering  to  22-34  //.  at  the  truncate  apex,  terminat- 
ing in  a  hair ;  hairs  of  two  kinds,  the  first  unicellular,  clavate, 
curved  or  hooked,  diam.  about  equal  to  that  of  the  supporting 
cell,  the  second  with  a  similar  but  narrower  basal  cell,  bearing 
at  its  apex  two  slender,  subcylindrical  cells,  each  in  its  turn 
with  2-4  similar  but  smaller  branches  ;  the  two  forms  of  hairs  in 
separate  zones ;  sporangia  strongly  calcified,  free  or  coherent  in 
rows  of  2-8;  aplanospores  obovoid  or  oblong-ellipsoid,  I4O-I9OX 
82-94  f"     Bahamas. 

Distinguished  by  the  fusiform  secondary  branches  and  the 
two  types  of  hairs,  in  distinct  zones  on  the  same  individual. 

5.     CYMOPOLIA  Lamouroux,  1816,  p.  292. 
Frond  branched,  consisting  of  a  series  of  bead-like  calcified 
joints,  connected  by  contracted,  flexible  uncalcified  portions,  in 
which  the  branching  occurs  ;  stem  and  branches  terminated  by 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  383 

tufts  of  branched,  pluricellular  hairs  ;  at  the  uncalcified  por- 
tions, whorls  of  sterile,  undivided  branches  ;  in  the  calcified 
portions,  whorls  of  branches  each  with  a  terminal  sporangium, 
and  branches  enclosing  and  passing  beyond  it ;  the  swollen 
ends  forming  the  surface  of  the  frond.  Development  of  spores 
unknown. 

C.  BARBATA  Lauiouroux,  1816,  p.  293;  Harvey,  1858,  p.  36, 
PI.  Xlyl.A.  ;  P.  B.-A.,  No.  28.  Frond  to  20  cm.  long,  varying 
much  in  density  of  branching  ;  joints  from  depressed-spherical 
to  cylindrical  and  several  diameters  long;  usually  1-3  mm. 
diani.  ;  '10-30  whorls  of  branches  in  a  joint,  20-30  branches  in  a 
whorl ;  sporangia  globose  or  short-pyriform,  160-200  p.  diam. 
Fig.  146.  Fla.,  W.  I. 

C.  rosarium  L,amouroux  and  C.  vicxicana  J.  G.  Agardh  repre- 
sent extreme  forms,  the  former  with  joints  mostly  globular,  the 
latter  with  joints  mostly  cylindrical.     A  single  plant  will  often 
have   branches   representing  these   extremes,  which   therefore 
should  not  have  even  varietal  rank. 

'  6.  DASYCLADUS  Agardh,  1827,  p.  640. 
Stem  unbranched,  cylindric-clavate,  uncalcified,  attached  at 
the  base  by  a  lobed  expansion,  and  bearing  in  the  upper  part 
whorls  of  about  12  ramuli  each;  ramuli  repeatedly  branching, 
each  branch  a  distinct  cell ;  gametangia  spherical,  terminal  on 
the  first  cell  of  a  rarnulus  and  surrounded  by  its  branches, 
producing  biciliate  gametes,  by  whose  union  is  formed  a 
zygote,  germinating  immediately. 

D.  CLAVAEFORMis  (Roth)   Agardh,    1828,    p.    16;    Kiitxing, 
1856,  PI.  XCI,  fig.  2  ;  P.  B.-A.,  No.  170.     Fronds  gregarious, 
2-4  cm.  high,  about  5  mm.  diam.  ;  whorls  of  ramuli  closely  set ; 
gametangia  400-550  /x  diam.     Fig.  142.     Fla.,  W.  I. 

Mediterranca  n . 

With  the  exception  of  a  short  basal  portion,  the  whole  of  the 
axis  is  covered  with  whorls  so  closely  set  as  to  form  an  appar- 
ently solid  mass,  the  individual  whorls  being  quite  indistin- 
guishable. In  drying  the  plant  usually  gives  out  a  brownish- 
yellow  fluid,  staining  the  paper  on  which  it  is  mounted. 
7.  BATOPHORA  J.  G.  Agardh,  1854,  p.  108. 

Vegetative  frond  as  in  Dasycladus ;  sporangia  chiefly  lateral 
on  the  ramuli  and  their  branches,  producing  aplanospores. 

B.  OERSTEDI  J.  G.  Agardh,  1854,  p.  108 ;  P.  B.-A.,  No. 
1490;  Botryophora  Conqucrantii  Cramer,  1890,  p.  6,  PL  IV,  fig. 
i  ;  B.  occidentalis  P.  B.-A.,  No.  667  ;  Coccodadus  occidentals  var. 


384     TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

laxus  Howe,  1904,  p.  95,  PI.  VI,  figs,  i  and  2.  Fronds  up  to 
10  cm.  high,  rather  soft  and  flaccid,  10-13  mm.  diam.  ;  whorls 
distinct,  not  very  close  ;  sporangia  ellipsoid  to  pyriform-sub- 
clavate,  500-1000X325-450  //.,  lateral  or  occasionally  terminal  on 
branches  of  t&e  first  to  the  fourth  orders  ;  aplanospores  ellipsoid, 
50-70  /u,  diam* ,  \y2  times  as  long,  in  a  single  layer  on  the  inner 
surface  of  the  sporangium.  Fig.  145.  Fla.,  W.  I. 

Var.  OCCIDENTALS  (Harv.)  Howe  19053,  p.  579;  Dasydadus 
occidentalis  Harvey,  1858,  p.  38,  Pi.  XLJ.B.  PYonds  shorter 
and  smaller,  whorls  more  closely  set,  ramuli  less  branched ; 
sporangia  spherical  or  nearly  so  ;  aplanospores  more  numerous, 
nearly  filling  the  sporangium.  With  the  type. 

The  form  described  as  B.  Ocrstedi  is  a  plant  of  quiet  brackish 
waters ;  the  var.  occidentalis  inhabits  exposed  shores,  and  quite 
resembles  Dasydadus ;  like  the  latter,  the  plants  stain  paper 
yellow,  while  plants  of  the  type  do  not. 

Family  5.     SPHAEROPL,EACEAE. 

Frond  an  unattached,  monosiphonous,  unbranched-filament, 
consisting  of  long,  cylindrical,  multinucleate  cells,  each  with 
many  minute,  disk-shaped  chromatophores  arranged  in  distinct 
zones,  and  many  pyrenoids  ;  sexual  reproduction  by  antheridia 
and  oogonia,  which  may  be  formed  in  the  same  or  in  separate 
filaments  ;  antheridia  formed  of  vegetative  cells,  unchanged  in 
shape  and  size,  the  contents  becoming  orange  colored,  and 
transformed  into  a  large  number  of  long-clavate  or  spindle- 
shaped,  biciliate  spermatozoids,  escaping  through  numerous 
openings  in  the  cell  wall  ;  oogonium  from  a  vegetative  cell,  un- 
changed in  shape  or  size,  the  contents  transformed  into  numer- 
ous spherical,  uninucleate  oospores,  fertilized  by  spermatozoids 
entering  the  cell  by  numerous  openings ;  oospore  after  fertiliza- 
tion brick-red,  with  three  colorless  membranes,  the  outer  mem- 
brane ample  and  with  wavy  folds ;  germinating  oospore  produc- 
ing 1-8  biciliate  zoospores,  which  on  germination  are  much 
elongated,  and  ultimately  form  a  filament  like  the  normal,  but 
with  pointed  ends ;  unfertilized  oospores  may  sometimes  ger- 
minate parthenogenetically. 

A  rather  isolated  family,  represented  by  only  one  genus. 

SPHAEROPLEA  Agardh,  1824,  p.  XXV. 
Characters  of  the  family. 

S.  ANNULINA  (Roth)  Agardh,  1824,  p.  76;  Wolle,  1887,  p. 
104,  PI.  CXXIII,  figs.  1-5;  P.  B.-A.,  No.  317.  Filaments  27- 
72  ju.  diam.,  cells  8-20  diam.  long  ;  20-30  zones  of  chromatophores 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  385 

in  a  cell;  oospores  usually  in  two  longitudinal  series,  11-26 /A 
diam.,  including  membrane.  Fresh  water.  Fig.  141.  Minn., 
Cal.  Europe. 

A  plant  of  shallow,  easily  dried  pools  ;  the  oospores  retaining 
vitality  for  years,  and  germinating  when  again  moistened.  Of 
wide  distribution  in  isolated  stations.  Klebahu,  1899,  divides 
>S.  annulina  into  two  species,  5".  crassi septa  (Heinrich)  Klebahn, 
and  6".  Braunii  Kiitzing  ;  the  former  with  filaments  27-35  /* 
diam.,  500-1200  /A  long,  oospores  11-19  /"•  diam.,  including  mem- 
brane, mostly  14 /A,  dissepiments  thick,  often  with  conical  pro- 
jections ;  the  latter  with  cells  42-65X250-1400  p.,  oospores  13-26 
/A,  mostly  17-19  /A,  dissepiments  relatively  thin  and  even. 
Whether  there  are  two  distinct  species,  or  only  two  forms  or 
varieties  of  6".  annulina,  is  hardly  certain  ;  in  the  former  case  it 
would  not  seem  that  the  name  of  5".  annulina  should  be  given 
up  in  favor  of  S.  crassisepta  ;  all  American  specimens  examined 
are  of  the  crassisepta  type. 

Order  VI.     SIPHONALES. 

v 

Fronds  filiform,  usually  much  branched  or  developing  into 
various  forms,  continuous  without  dissepiments  in  the  vegeta- 
tive condition,  multinucleate,  with  many  lens-  or  disk-shaped 
chromatophores. 

KEY  TO  THE  FAMILIES  OK  SIPHONALES. 

i.     Sexual  reproduction  by  motile  gametes  or  unknown.  2. 

i.     Sexual  reproduction  by  non-motile  oospores  and  motile  spermato- 

zoids.  6.    VAUCHERIACEAE. 

2.     Frond   differentiated  into  root,  stem  and  branches,  the  latter  of 
very  varied  form  ;  reproduction  unknown. 

5.    CAULERPACEAE. 

2.     Frond  filiform,  branching  ;  not  differentiated  as  above.  3. 

3.     Filaments  interwoven  to  form  fronds  of  definite  form. 

i.     CODJACEAK. 

3.     Filaments  branching,  not  interwoven.  4- 

4.     Sexual  reproduction   by  large   female    and    small    male  gametes; 
asexual  reproduction  unknown  ;  branching  more  or  less  plumose. 

2.     BRYOPSIDACEAK. 

4.     Sexual  reproduction  unknown  ;  branching  irregular.  5. 

5.     In  tissues  or  shells  of  plants  or  animals  ;    asexual   reproduction  by 

aplanospores.  4-     PHYLLOSII-HONACKAE. 

5.     Free,  marine;  asexual  reproduction  by  large,  multicilate  zoospores. 

3.    DERBESIACEAE. 


386  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Family  i.     CODIACEAE. 

Frond  except  in  the  lowest  forms  of  definite  shape,  composed 
of  interwoven,  continuous,  branching  filaments,  sometimes  ap- 
parently pluricellular  by  constrictions,  calcified  or  not.  Asex- 
ual reproduction  by  zoospores  and  aplanospores,  formed  in  spo- 
rangia ;  sexual  reproduction  by  zoogametes,  the  sexes  either 
similar  or  differing  in  size. 

KEY  TO  THE  GENERA  OF  CODIACEAE. 

i.  Not  calcified  nor  stipitate,  soft  and  spongy  ;  cortical  layer  formed  of 
the  swollen  ends  of  the  longitudinal  filaments.  Subfamily  COD- 
IOIDEAE.  i.  CODIUM. 

i.  Stipitate  or  of  seriate  disks,  often  calcified;  cortical  layer,  when 
present,  formed  of  lateral  branches,  usually  smaller  than  the 
longitudinal  filaments.  Subfamily  UDOTOIDEAE.  2. 

2.     Frond  terminating  in  a  penicillate  tuft  of  free  filaments. 

3.    PENICILLUS. 

2.     Frond  not  terminating  in  free  filaments.  3. 

3.     Frond  of  a  branching  series  of  disks.  7.     HAUMEDA. 

3.     Disks  terminal  or  wanting.  4. 

4.     Frond  terminating  in  numerous  flat  expansions. 

4.    RHIPOCEPHALUS. 

4.     Frond  not  terminating  in  numerous  flat  expansions.    <j  5. 

5.     No  definite  cortical  layer.  2.     AVRAINVII^EA. 

5.     Cortex  present  either  on  stipe  or  lamina.  •  6. 

6.     Cortex  of  divaricate,  labyrinthiform  branches  always  present. 

6.    CLADOCEPHALUS. 
6.     Cortex  of  lamina  wanting,  or  of  short,  little  divided  branches. 

5.    UDOTEA. 

Subfamily  CODIOIDEAE. 
i.     CODIUM  Stackhouse,  1795,  p.  XVI. 

Frond  of  spongy  texture,  of  very  varying  form,  consisting  of 
branching,  continuous  filaments,  their  swollen  ends,  "  utricles  " 
closely  packed  to  form  a  cortical  layer ;  sexual  reproduction  by 
zoogametes,  produced  in  subovoid  sporangia,  borne  laterally  on 
the  utricles  ;  large  biciliate  female  gametes  produced  in  spo- 
rangia with  very  dark  green  contents ;  small  biciliate  male 
gametes  produced  in  sporangia  with  yellowish  contents;  male 
and  female  usually  produced  on  distinct  individuals,  but  occa- 
sionally on  the  s'ame  individual ;  by  the  union  of  the  two  sexes 
a  zygote  is  produced,  germinating  immediately  ;  no  asexual 
reproduction  is  known,  but  is  probable  that  female  zoospores 
sometimes  germinate  parthenogenetically. 

The  species  of  Codium  here  recognized  are  based  either  on  ex- 
ternal form,  which  is  more  or  less  variable  in  each  species,  or  on 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  387 

the  size  of  the  utricles,  which  varies  within  quite  wide  limits. 
It  is  probable  that  when  the  genus  is  thoroughly  studied,  pres- 
ent arrangements  will  be  considerably  changed. 

KEY   TO   THH    Sl'KCIKS   OF    CODIUM. 

i.     Forming  a  continuous  expanded  incrustation.  2. 

i.     Not  forming  a  continuous  expanded  incrustation.  3. 

2.     Utricles  usually  50-60  /u,  rarely  100  M  diam.  i.     C.  adhaerens. 

2.     Utricles  usually  125-200  /x,  rarely  300 /u  diam.          2.     C.  difforinc. 
3.     Frond  globose  to  pyriform.  3.     C.  Ritteri. 

3.     Frond  branched,  cylindrical  or  compressed.  4. 

4.     Frond  creeping,  attached  by  holdfasts.  4.     C.  repens. 

4.     Frond  erect.  5. 

5.     All  or  part  of  the  utricles  inucrouate.  9.     C.  mucronatum. 

5.     Utricles  blunt,  smooth.  6. 

6.     Branches  usually  constricted  at  base.  6.     C.  isthmocladum. 

6.     Branches  not  usually  constricted  at  base.  7. 

7.     Frond  normally  cylindrical  throughout;  utricles  seldom  200  /u  diam. 

5.     C.  toHientosum. 
7.     Frond  normally  more  or  less  compressed.  8. 

8.     Utricles  usually  400  n  diam.  or  more.  7.     C.  elongatum. 

8.     Utricles  usually  less  than  250  p.  8.     C.  Lindenbergii. 

1.  C.  ADHAERENS  (Cabr.)  Agardh,    1822,  p.  457  ;  Harvey, 
1846-51,  PI.  XXXV. A;   P.  B.-A.,   No.   523.     Forming  an  ex- 
panded,  incrusting  layer,  closely  adherent  to  the  substratum, 
dark   green,    lubricous,  increasing   by  marginal  growth,  with 
rounded  lobes  ;  the  filaments  and  utricles  united  by  firm   gela- 
tine ;  utricles  clavate,  50-60,  rarely  100  /udiam.,  sometimes  with 
long,  cylindrical  lower  part.     On  exposed  rocks.     Vancouver  to 
Cal.  Europe,  Asia,  Oceanica. 

Forming  a  firm  crust,  about  i  cm.  thick,  on  rocks  ;  quite  dis- 
tinct from  our  other  species,  except  C.  difforme,  which  has  a 
similar  habit,  but  larger  utricles. 

2.  C.  DIFFORME   Kiitzing,    1843,  p.  300;    1856,  PI.  XXXV, 
fig-  99;  Vickers,  1908,  p.  22,  PI.  XXV.     Habit  like  that  of  C. 
adhaerens ;  utricles    125-200,   rarely  up  to   300  fj.  diam.     Fla., 
W.  I.  Mediterranean,  warmer  Atlantic,  Pacific, 

Apparently  a  plant  of  warmer  waters,  while  C.  adhaerens  ex- 
tends considerably  farther  north. 

3.  C.  RITTERI  Setchell  and  Gardner,  1903,  p.  231,  PI.  XVII. 
Frond  globose  to  pyriform,  up  to  3  cm.  high,  attached  by  a  dis- 
tinct stipe-like  base,  solid,  the  center  consisting  of  a  felt-like  mass 
of 'fine    filaments;   utricles   pyriform,    blunt,    150-400   p.   diam. 
older  ones  usually  swollen  in  the  middle,  and  with  the  mem- 


388          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

brane  at  the  tip  somewhat  thickened  at  the  central  part  and 
projecting  inwards.    Alaska  to  Vancouver. 

Nearest  allied  to  C.  mamillosum  Harv.,  but  that  species  has 
balloon-shaped  utricles,  1-2  mm.  diam. 

4.  C.  REPENS  Crouan  in  Vickers,  1905,  p.  56;   1908,  p.  23, 
PI.  XXIX  ;   C.  tenue  var.  repens  Crouan  in  Maze  and  Schramm, 
1870-77,    p.    107.     Branching   like    that  of    C.   tomcntosum  but 
branches  prostrate  and  entangled,  attaching  themselves  to  the 
substratum  by  short  special  branches  ;  utricles  150-300  p.  diam. 
On  rocks  at  low  tide.     Barbados,  Guadeloupe. 

5.  C.  TOMENTOSUM  (Huds.)  Stackhouse,    1795,   p.   21,    PL 
VII;  Harvey,  1846-51,  PI.  XCIII ;   1858,  p.  29,  in  part  ;  Vick- 
ers, 1908,  p.   22,   PL   XXVI;   P.  B.-A/,  No.  168.     Frond  erect, 
cylindrical,    dichotomously   branched,  more  or  less   fastigiate, 
surface  smooth  and   soft;    utricles  obovate-clavate,   100-150  p., 
rarely  200  yu.   diam.,   3-6   diam.  long.,  apex  obtuse,    unarmed. 
N.  C.  to  Fla.;   W.  I.  Europe,  Asia,  Africa,  Occanica. 

A  cosmopolitan  species,  but  many  forms  once  included  here 
have  been  removed,  and  it  may  be  that  a  careful  comparison 
would  considerably  reduce  the  number  of  localities  for  C.  tomcn- 
tosum. The  principal  distinctions  from  similar  species  are  found 
in  the  cylindrical  frond,  and  the  unarmed  tips  of  the  utricles. 

6.  C.  ISTHMOCLADUM  Vickers,  1905,  p.  57;   1908,  p.  23,  PL 
XXVIII.     Frond  dichotomously  branched,  the  branches  usu- 
ally constricted  at  the  base  ;    utricles  200-300  p.  diam.     Barba- 
dos, Guadeloupe. 

7.  C.  ELONGATUM  Agardh,   1822,  p.  454;  Vickers,  1908,  p. 
22,    PI.    XXVII;  P.  B.-A.,    No.    627.     Frond   dichotomously 
branched,  often  much  elongate,  younger  divisions  terete,  older 
compressed,  especially  below  the  dichotomies,  being  there  dis- 
tinctly cuneate  ;    utricles  obovate-clavate,  300-400  ju,  diam.,  5-6 
times  as  long  as  the  greatest  diam.     N.  C.  to  Fla.,  W.  I. 

Europe,  Africa,  So.  America. 

The  younger  plants  resemble  C.  tomentosum,  but  the  flatten- 
ing is  marked  in  older  plants ;  in  some  cases  all  parts  except 
the  younger  tips  are  quite  broadly  cuneate. 

8.  C.  L,INDENBERGII  Binder  in   Kiitzing,   1856,  p.  34,   PL 
XCVII ;  P.   B.-A.,   No.  628.     Frond  di- polychotomous,  com- 
pressed or  flat  in  all  parts,  segments  cuneate,  terminal  linear- 
lanceolate  ;  utricles  clavate,  80-150^  diam.,  3-4  times  as  long 
as  the  greatest  diam.     Cal.  Africa. 

The  fronds  in  this  species  are  sometimes  triangular  or  reni- 


THE  GRKKN  ALGAE  OF  NORTH  AMI-: RICA          389 

form  and  undivided  ;  an  extreme  much  beyond  anything  in  C. 
elongation  ;  for  ordinary  forms  the  difference  in  si/.e  of  utricles 
is  sufficient  distinction. 

9.  C.  MUCRONATUM  J.  G.  Agardh,  1886,  p.  43.  Frond 
cylindrical,  more  or  less  regularly  dichotomously  fastigiate,  sur- 
face more  or  less  roughish ;  utricles  cylindric-clavate,  5-10 
diam.  long,  terminating  in  a  distinct  mucro. 

As  described  by  Agardh,  this  species  is  divided  between  three 
varieties,  with  no  definite  typical  form  ;  it  seems  to  take  a  place 
in  the  Pacific  the  same  as  that  occupied  by  C.  tomcntosum  in  the 
Atlantic,  and  it  is  probable  that  most,  if  not  all  reports  of  the 
latter  from  the  Pacific,  really  refer  to  this  species. 

Var.  CAIJFORNICUM  J.  G.  Agardh,  1886,  p.  44,  PI.  I,  fig.  3; 
P.  B.-A.,  No.  229.  Utricles  in  younger  parts  of  the  frond 
cylindrical,  ending  in  a  very  acute  mucro  ;  in  the  older  parts 
clavate,  with  a  blunter  mucro.  Fig.  144.  Alaska  to  Mexico. 

Var.  NOVAE  ZELANDIAE  J.  G.  Agardh,  1886,  p.  44.  Utricles 
in  younger  parts  subcylindrical,  with  a  short  mucro  ;  in  older 
parts  clavate,  mucro  wanting  or  very  inconspicuous.  Van- 
couver. N.  Zealand. 

In  var.  californic-inn  the  mucronate  utricles  are  so  well  devel- 
oped that  the  surface  of  the  frond  appears,  even  to  the  naked 
eye,  not  so  smooth  as  that  of  C.  torn  cut  osinn.  In  var.  novae 
zclandiae  they  are  much 'less  noticeable,  and  some  care  is  re- 
quired to  distinguish  this  variety  from  C.  tomcntoswn. 

2.     AvRAiNviUvEA  Decaisne,  1842,  p.  108. 

Fronds  not  calcified,  sessile  or  stipitate,  coarse,  greenish, 
brownish  or  blackish,  composed  of  inarticulate,  cylindrical  or 
moniliform,  dichotomous,  interwoven  filaments,  terminating 
above  in  a  somewhat  flabelliform  expansion  or  in  digitate  lobes, 
below  in  a  mass  of  rhizoids  or  a  rhizome  ;  chromatophores  mi- 
nute, rounded  or  fusiform,  usually  with  a  pyrenoid  ;  reproduc- 
tion by  aplanospores  (?)  formed  in  small  number  in  sporangia 
terminal  on  short  branches  projecting  from  the  surface. 

A  tropical  genus  of  coarse,  unsightly  algae,  growing  abun- 
dantly in  muddy  shallow  water,  but  extending  also  to  consider- 
able depths. 

KEY  TO  THE  SPECIES  OF  AVRAINVILLEA. 
I.     Upper  part  a  distinct  flabelluni. 
i.     Upper  part  digitately  lobed.  i.     A.  Rawsoni. 


390          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

'2.     Surface  of  flabellum  smooth  or  sinoothish.  3.     A.  levis. 

2.  Surface  of  flabellum  velutinous,  spongy  or  strigose.  3. 

3.  Interior  filaments  of  flabellum  moniliform.  2.  A.  nigricans. 

3.  Interior  filaments  of  flabellum  cylindrical  with  basal  constrictions. 

4.  A.  loiigicanlis. 

1.  A.  RAWSONI  (Dickie)  Howe,  1907,  p.  510,  PI.  XXX  ;   P. 
B.-A.,  No.  1481.     Frond  formed  of  more  or  less  dense,  terete, 
clavate  or  fusiform,  digitate  lobes,  not  developing  a  flabellum  ; 
filaments  cylindrical  to  subtorulose,  always  strongly  constricted 
just  above  a  dichotomy,  rather  thin-walled,  30-70  /A  diam.;  color 
rather   light  green  when  growing,  brownish  or  blackish  when 
dried.     W.  I. 

The  digitately  lobed  frond,  much  resembling  some  of  the 
common  digitate  sponges,  sufficiently  distinguishes  this  from 
our  other  species.  The  material  distributed  in  P.  B.-A.,  No. 
770  as  A.  longicaulis  and  No.  771  as  A.  nigricans,  was  largely 
A.  Rawsoni,  but  also  with  some  A.  nigricans,  as  now  defined. 

2.  A.  NIGRICANS    Decaisne,    1842,    p.  96;   Howe,    1907,  p. 
508,  PI.  XXVIII,  figs.  8-25  ;  A.  longicaulis  Murray  and  Boodle, 
1889,  p.  70,  PI.  CCLXXXVIII,  figs.  1-5.     Flabellum  suborbic- 
ular  to  cuneiform,  irregularly  and  obtusely  lobed  ;  coriaceous, 
sessile    or   stipitate,  from  a  more  or   less  distinct   subterranean 
rhizome  ;  filaments  very  regularly  moniliform  ;  those  of  the  in- 
terior 50-70  /u,  diam.,  near  the  surface  about  30  p.,  with  closer  set 
constrictions  ;  sporangia  clavate  to  globose,  350-800X200-350  /*; 
spores  ovoid,  pyriform,  or  elongate-ellipsoidal,  130-300X66-120 
p..     Color  dark  brown  or  blackish.     W.  I.,  Fla.  Brazil. 

A  coarse  and  unsightly  plant,  forming  dense  growths  under 
the  surface  of  the  mud  in  shallow  sheltered  waters ;  the  tuber- 
like  rhizome  is  usually  infested  with  many  minute  animals. 
The  texture  of  the  flabellum  is  quite  loose,  not  entirely  opaque, 
when  held  against  the  light. 

Forma  FULVA  Howe,  P.  B.-A.,  No.  1480.  Flabellum  thicker, 
more  spongy  ;  stipe  flatter,  broader  and  less  differentiated  ;  fila- 
ments coarser,  less  regularly  moniliform,  more  frequently  and 
divaricately  forked  ;  color  more  yellowish.  With  the  type. 
The  sporangia  noted  above  for  this  species  were  found  on  an 
individual  of  forma  fulva. 

3.  A.  LEVIS   Howe,    igosa,  p.  565,    PI.   XXIII,   fig.  i  ;   PL 
XXVI,  figs.  8-10 ;   P.  B.-A.,  No.  1478;  A.  sordida  Murray  and 
Boodle,    1889,  p.    70.*     Flabellum   cuneiform-obovate    to  reni- 

*  A.  asarifolia  Borgesen,  1908,  p.  34,  fig.  4,  PI.  Ill,  is  hardly  to  be  dis- 
tinguished from  A.  levis ;  the  specimens  of  the  latter  distributed  as  P. 
B.-A.,  No.  1478  are  not  at  the  fullest  development,  but  other  specimens 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  391 

form-orbicular  with  cordate  base,  1-7  cm.  wide,  entire  or  some- 
what lobed,  compact,  surface  smooth  or  slightly  wrinkled,  gen- 
erally zonate  ;  stipe  cylindrical  or  flattened,  ^-4  cm.  high,  from 
a  short  base  ;  filaments  slender,  6-24  ft  diam.,  in  the  interior  up 
to  35  n,  cylindrical  or  slightly  torulose  ;  color  olive  or  ashy 
brown.  Fig.  147.  W.  I. 

Externally  distinguished  by  the  shorter  stipe,  relatively 
broader  lamina,  and  smoother  surface  ;  but  as  there  is  much 
variation  in  all  these  characters,  inspection  of  the  filaments  is 
necessary  for  anything  like  certainty. 

4.  A.  LONG'ICAULIS  (Kiitz.  !)  Murray  and  Boodle,  1889,  p. 
70;  P.  B.-A.,  No.  1479;  A.  Mazei,  Murray  and  Boodle,  1889, 
p.  71  ;  Rhipilia  longicaulis  Kiitzing,  1858,  p.  13,  PI.  XXVIII, 
fig.  2  ;*  Flabellum  cuneate  or  oblong,  from  a  usually  long  stipe, 
up  to  15  cm.,  sometimes  but  not  always  from  a  basal  rhi/.ome  ; 
filaments  cylindrical,  except  for  sharp  constrictions  above  the 
forkings,  28-70  p.  diam.,  the  outer  filaments  sometimes  down  to 
20  p..  W.  I. 

Distinguished  from  A.  nigricans  by  the  cylindrical  filaments  ; 
in  external  characters  the  two  are  very  similar,  but  A.  longicau- 
lis usually  has  a  longer  stipe,  less  developed  rhizome,  and  more 
regularly  cuneate  flabellum.  A.  Icvis  is  generally  a  smaller 
plant  and  has  a  thinner  flabellum,  but  sometimes  it  is  necessary 
to  determine  the  size  of  the  filaments,  which  are  much  smaller 
in  the  latter  species. 

3.     PENICILLUS  Lamarck,  1813,  p.  297. 
Frond  penicillate,  with  distinct,  calcified  stipe,  from,  the  top 

from  the  same  locality  are  large  and  well  developed,  and  agree  well  in 
habit  with  A.  asarifolia.  The  filaments  of  the  latter  are  torulose, 
but  in  this  respect  A.  levis  varies  considerably.  In  the  same  paper, 
p.  28,  fig.  i,  Bb'rgesen  notes  under  the  name  of  A.  comosa  (Bail,  and 
Harv.)  Murray  and  Boodle,  a  single  specimen  from  the  Danish  West 
Indies.  Chlorodesmis  comosa  Bailey  and  Harvey  has  been  reported  from 
many  stations  in  the  Pacific,  but  this  seems  to  be  the  only  definite  report 
of  it  in  the  North  Atlantic.  As  Bb'rgesen  speaks  of  his  plant  differing  in 
some  particulars  from  the  ordinary  form,  it  may  be  well  to  suspend  judg- 
ment for  the  present.  Moreover,  the  inclusion  of  Chlorodesmis  comosa 
in  Avrainvillea  by  Murray  and  Boodle  seems  rather  unnecessary,  and  it 
would  certainly  give  the  genus  a  much  broader  and  less  definite  exten- 
sion than  that  commonly  received  and  here  used.  At  p.  36,  fig.  6,  Bb'rg- 
esen mentions  as  Avrainvillea  sp  ?  a  form  which  may  well  be  included 
in  A.  levis  as  here  understood. 

*See  Howe,  igosa,  p.  586;  1907,  p.  510,  as  to  the  type  specimen  of  Rhi- 
pilia longicaulis;  Murray  and  Boodle  having  first  used  the  binomial 
Avrainvillea  longicaulis,  must  be  cdnsidered  its  authors,  although  the 
name  does  not  belong  to  the  plant  to  which  they  applied  it. 


3Q2  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

of  which  issue  in  all  directions,  free,  dichotomously  branched 
filaments,  inarticulate  but  with  occasional  constrictions  ;  base  a 
mass  of  rhizoids  ;  reproduction  unknown. 

The  characteristic  brush-like  form  in  the  species  of  this  genus 
easily  distinguishes  them  from  all  our  other  algae  except  Rhipo- 
cephalus  ;  in  the  latter  the  filaments  are  united  into  many  fan-like 
expansions,  while  in  Penicillus  they  are  free,  and  issue  in  all 
directions ;  the  species,  however,  are  not  very  strongly  marked, 
and  it  is  often  a  matter  of  difficulty  to  decide  to  which  of  them  a 
specimen  is  to  be  tef erred. 

KEY  TO  THE  SPECIES  OF  PENICILLUS. 
i.     Filaments  stout  but  relatively  scanty  ;  stipe  soft. 

3.    P.  LaiHOurouxii. 

i.     Filaments  of  moderate  size,  abundant ;  stipe  firm.  2. 

2.     Stipe  stout  and  short ;  head  pyriforrn.  4.     P.  pyrifonnis. 

2.     Stipe  longer  ;  head  rounded.  3. 

3.     Stipe  slender,  smooth  ;  filaments  much  calcified,     i.     P.  capitatus. 

3.     Stipe  stout,  rough  ;  filaments  slightly  calcified.     2.    P.  dumctosus. 

1.  P.  CAPITATUS  I/amarck,  1813,  p.  299  ;  Harvey,  1858,  p.  45, 
PI.  XLJII.B  ;   P.  B.-A.,  Nos.  271,  1475.     Stipe  up  to  10  cm.  high, 

'slender,  not  over  5  mm.  diam.,  smooth,  cylindrical,  having  at 
the  summit  a  subspherical  head  composed  of  slender,  dichoto- 
mous  filaments,  usually  100-200  fj.  diam.,  with  slight  and  dis- 
tant constrictions,  much  calcified  ;  stipe  extending  to  the  center 
of  the  head.  Common  in  shallow  water.  Fig.  149.  Fla., 
W.  I. 

2.  P.  DUMETOSUS  (lyamour.)   Decaisne,   1842,  p.  97;  Har- 
vey, 1858,  p.  44,   PI.  XLHI.A;   P.  B.-A.,  No.  769.     Stipe  to  8 
cm.  high,   12-25  mm.  diam.,  cylindrical  or  compressed,  surface 
uneven  and  granular  ;  at  the  summit  a  mass  of  dichotomous  fil- 
aments about  as  long  as  the  stipe,  500-800  /*  diam.,  cylindrical 
or   compressed,    somewhat    calcified,    distinctly    constricted    at 
rather  distant  intervals.     Fla.,  W.  I. 

A  stouter  species  than  P.  capital  us,  with  shorter  and  rougher 
stipe,  and  larger  head  with  larger  and  usually  less  calcified  fila- 
ments. It  is  rather  common  in  our  warmer  waters,  but  not  as 
common  as  P.  capitatus. 

3.  P.  lyAMOUROUxn  Decaisne,  1842,  p.  97.      Stipe  3-4  cm. 
long,  6-8  mm.  diam.,  smooth,  rather  soft  and  compressible,  not 
penetrating  the  head;  head  globose,  3-4  cm.  diam.,   filaments 
not    abundant    for    the    genus1,    400-500   //.   diam.,    ascending, 
strongly  calcified.     Bahama,  Jamaica. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  393 

The  soft  stem,  usually  flattened  or  canaliculate  when  dried, 
and  the  stout  but  not  very  abundant  filaments  of  the  head,  dis- 
tinguish this  from  the  other  species. 

Var.  GRACILIS  A.  and  E.  S.  Gepp,  1905,  p.  2,  PI.  CCCCLX- 
VIII,  fig.  2  ;  P.  B.-A.,  No.  1476.  Filaments  more  abundant, 
300-400  /txdiam.  With  the  type. 

4.  P.  PYRIFORMIS  A.  and  E.  S.  Gepp,  1905,  p.  i,  PI. 
CCCCLXVIII,  fig.  i  ;  P.  B.-A.,  No.  1477.  Stipe  1-3  cm. 
long,  6-7  mm.  thick,  slightly  compressed,  hardly  entering  the 
head,  surface  rough  ;  head  pyriform,  5-7  cm.  long,  3-4.5  cm. 
diam.,  dense,  drying  glaucous  green;  filaments  calcified,  as- 
cending, densely  interwoven,  150-200  /x  diam.  In  shallow  water. 
Fla.,  Bermuda,  Bahama. 

Resembles  P.  capitatus,  but  with  shorter  and  relatively  stouter 
stipe,  not  penetrating  far  into  the  head  ;  the  latter  is  pyriform 
rather  than  spherical,  and  the  filaments  are  more  densely  matted. 

4.     RHIPOCEPHALUS  Kiitzing,  1843,  p.  311. 

Frond  with  erect  stipe,  bearing  at  the  summit  a  dense  cluster 
of  minute,  cuneate,  flabellate  expansions,  formed  of  the  laterally 
united  filaments  ;  otherwise  like  PeniciUus. 

R.  PHOENIX  (Ell.  and  Sol.)  Kiitzing,  1849,  p.  506  ;  P.  B.-A., 
No.  1030;  PeniciUus  Phoenix  Harvey,  1858,  p.  46,  PI.  XLIII.C. 
.Stipe  to  10  cm.  high,  about  8  mm.  diam.,  terete,  slightly  taper- 
ing upwards,  strongly  calcified,  smooth  ;  the  upper  part  con- 
cealed by  the  round,  oblong,  or  conical  head  ;  flabella  compos- 
ing the  head  5-20  mm.  long,  calcified,  monostromatic,  each 
composed  of  the  laterally  united  dichotomous  ramification  of  a 
single  basal  filament :  filaments  75-100^ diam.  Fig.  150.  Fla., 
W.  I. 

The  flabellately  united  filaments  distinguish  this  from  all 
species  of  PeniciUus,  and  there  is  no  other  genus  for  which  there 
is  any  danger  of  mistaking  it ;  but  it  varies  much  in  general 
dimensions,  as  well  as  in  proportion  of  parts.  In  Gepp,  1905, 
p.  4,  the  following  forms  are  indicated. 

Forma  TYPICUS  Gepp,  1905,  p.  4.  Flabella  about  15  mm. 
long,  forming  an  oblong,  smooth  head. 

Forma  BREVIFOLIUS  Gepp,  1905,  p.  4.  Flabella  5-10  mm. 
long,  generally  in  densely  imbricate,  ascending  whorls,  forming 
an  elongate-conical  head  ;  stipe  percurrent  through  the  head. 
Fla.,  Bahama,  Guadeloupe,  Jamaica. 

Forma  LONGIFOLIUS   Gepp,  1905,  p.  4,   PI.  CCCCLXVIII, 


394          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

fig.  3.  Flabella  20  ram.  long  and  more,  irregular,  deeply  and 
irregularly  laciniate,  ascending  or  divergent,  forming  a  bristly 
head.  Fla. 

5.     UDOTEA  L,amouroux,  1813,  p.  27. 

Frond  arising  from  a  mass  of  rhizoids  ;  stipe  erect,  with  dis- 
tinct cortex,  terminating  in  a  flabelliform,  more  or  less  distinctly 
zonate  lamina,  consisting  of  continuous,  branching  filaments 
with  more  or  less  numerous  short  branches,  attached  to  each 
other  by  short  processes,  and  sometimes  developing  laterally  in- 
to a  more  or  less  definite  cortex  ;  calcification  more  or  less  com- 
plete ;  reproduction  unknown. 

Distinguished  from  Avrainvillea  by  the  corticated  stipe  ;  from 
Cladocephalus  by  the  cortex  of  the  lamina,  when  present,  not  be- 
ing formed  of  densely  packed,  labyrinthine  branches  as  in  the 
latter. 

The  evolution  of  all  the  forms  of  the  subfamily  Udotoideae 
from  a  branching  filament  like  Dichotomo siphon  is  best  shown  in 
this  genus.  In  the  Mediterranean  species  U.  minima  Ernst  the 
filaments  are  loosely  united  or  often  quite  free ;  from  this  to 
U.  Flabellum,  with  no  external  indication  of  the  original  fila- 
mentous structure,  the  intermediate  stages  can  be  seen  in  the 
different  species.  See  Ernst,  1904,  for  a  clear  statement  of  the 
matter. 

KEY  TO  THE  SPECIES  OF  UDOTEA. 

i.     Whole  flabellum  with  a  stony  coating.  2. 

r.     No  general  stony  coating.  3. 

2.     Branches  forming  the  cortex  of  the  lamina  capitate. 

6.     U.  argentea. 

2.     Cortical  filaments  not  capitate.  5.     U.  Flabellum. 

3.     Little  or  no  calcification.  i.     U.  tomentosa. 

3.     Individual  filaments  of  the  flabellum  calcified.  4. 

4.     Flabellum  with  a  cortex  of  spinulose  branches. 

4.     U.  spimilosa. 

4.     Flabellum  uncorticated.  5. 

5.     Flabellum  plane.  2.     U.  conglutinata. 

5.     Flabellum  concavo-convex  to  cyathiform.  3.     U.  cyathiformis. 

i.  U.  TOMENTOSA  (Kiitz.)  Murray,  1889,  p.  239;  Howe, 
1907,  p.  512.  Fronds  to  7  cm.  high,  bright  green,  uncalcified  ; 
stipe  terete  or  flattened,  2-4  mm.  wide,  simple  ;  flabellum  cunei- 
form to  obdeltoid,  3-5  cin.  long,  1-3  cm.  wide,  entire  or  lobed, 
little  or  not  at  all  zonate,  rather  thick,  spongy,  with  tomentose 


THE  GREEN  ALGAE  OF  NORTH  AMKKICA  395 

surface  ;  filaments  of  flabellum  35-70 /x  diam.,  the  lesser  branches 
more  or  less  attached  by  short  processes.     W.  I. 

2.  U.  CONGLUTINATA  (Soland.)  LamourouSc,   1816,  p.  312; 
Howe,  1909,  p.  96,  PI.  II ;   PI.  VIII,  figs.  11-13;  Fronds  to  10  cm. 
high,  greenish  or  whitish,  more  or  less  calcified  ;  stipe  subterete, 
above  flattened  and  passing  gradually  into  the  cuneate  base  of 
the  flat,  cuneate  to  suborbicular,  uncorticated,  simple  or  some- 
what lobed,  usually  zonate  flabellum  ;  longitudinal  filaments  of 
flabellum  28-60. /x  diam.,  twisted    and  interwoven;  branches  of 
the   stipe   cortex   slender,   flexuous    and    tortuous,   loosely  and 
irregularly  fastigiate,    ultimate  divisions  digitate,   subacute  or 
taper-pointed.     Fla.,  W.  I. 

To  be  carefully  distinguished  from  U.  cyathiformis,  which  is 
sometimes  quite  like  it  in  habit ;  the  characters  of  the  cortex  of 
the- stipe  should  determine  in  such  cases. 

3.  U.  CYATHIFORMIS  Decaisne,    1842,  p.  106 ;  Howe,  1909, 
p.   96,   PI.   Ill;  -PI.   VIII,   figs.   8-10  ;    U.  conglutinata  Vickers, 
1908,  p.  24,   PI.  XXXII;  P.   B.-A.,   No.    1482;     ?  U.  coni>lnti- 
nata    Harvey,    1858,    PI.    XL.C.     Frond    up   to   15    cm.   high, 
greenish,  becoming  whitish,   moderately  calcified  ;    stipe   sub- 
terete,   passing   abruptly  into    the    concavo-convex    to   cyathi- 
form,  entire  or  laciniate-fimbriate,  only  slightly  zonate,  uncorti- 
cated flabellum;  longitudinal  filaments  of  the  flabellum  40-125 
/x  diam.,  usually  60-100  /x,  nearly  straight,   parallel  and  rigid  ; 
branches  of  the  stipe  cortex  cymose-fastigiate,   ultimate  divi- 
sions very  short,   apices  truncate,   obtuse  or  truncate- capitate, 
seldom  over  50 /u.  long.     Fig.  154.     Fla.,  W.  I. 

The  cup-shaped  form,  from  which  this  species  has  its  name,  is 
sometimes  hardly  perceptible ;  but  the  other  characters  are 
more  uniform. 

4.  U.   SPINULOSA  Howe,    1909,  p.  97;   PI.  IV,  fig.  2;   PI. 
VIII,  figs.  1-7.     Frond  up  to  8  cm.  high,  grayish-green,  strongly 
calcified  ;  stipe  subterete,  flattened  above  and  passing  gradually 
into  the  cuneate  base  of  the  flat,  obovate,  longitudinally  striate 
but  hardly  zonate,  corticated  flabellum  ;  longitudinal  filaments 
of  the  flabellum  48-64 /A  diam.,  parallel  or  interwoven,   thickly 
beset  externally  with  short  processes  crowned  with   acuminate 
spines  ;    branches  of  the  stipe   cortex  4-6  times  dichotomous, 
ultimate  divisions  taper-pointed,  up  to  200  /x  long.     Bahamas. 

In  habit  somewhat  like  U.  conglutinata  and  U.  cyathiformis, 
but  quite  distinct  by  the  well  developed  cortex  of  short,  spinous 
branchlets. 

5.  U.  FI.ABKLLUM  (Ell.  and  Sol.)  Howe,   1904,  p.  94  ;   U. 


396          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

flabdlata  Lamouroux,  1816,  p.  311,  PI.  XII,  fig.  i;  Harvey, 
1858,  p.  26;  P..B.-A.,  No.  272.  Frond  up  to  15  cm.  high, 
stipe  short,  of  ten- indistinct  ;  flabellum /entire  and  cuneate-reni- 
form  or  divided  into  a  few  similar  lobes  ;  longitudinal  filaments 
of  the  flabellum  flexuous,  rather  distant,  their  short  ramuli 
forming  a  cortical  layer,  the  whole  covered  with  a  stony  in- 
crustation. Fla.,  W.  I. 

Not  to  be  mistaken  for  any  other  of  our  species,  none  of 
which  have  the  general  stony  coating. 

6.  U.  ARGENTEA  Zanardini,  1858,  p.  290,  PI.  XII,  fig.  i  ; 
Howe,  1909,  p.  99  ;  Gepp,  1909,  p.  386.  Calcified  ;  stipe  short  ; 
frond  thin,  subreniformly  flabellate,  longitudinally  striate,  only 
slightly  zonate,  repeatedly  proliferous  ;  lateral  branches  of  main 
filaments  abundant,  each  terminating  in  a  capitate  or  ungulate 
head.  W.  I.  Red  Sea,  Indian  Ocean. 

Among  our  better  known  species  U.  Flabellum  is  nearest  to 
U.  argentea,  but  the  latter  has  a  shorter  stipe,  is  of  thinner  text- 
ure with  more  manifest  radiate  markings,  along  which  it  appears 
sometimes  to  divide ;  as  it  is  plentifully  proliferous  from  the 
margin,  a  single  plant  may  develop  into  an  apparent  colony. 
Structurally  it  is  distinguished  by  the  capitate  form  of  the 
branches  composing  the  cortex. 

6.     CLADOCEPHALUS  Howe,  i905a,  p.  569. 

Not  calcified ;  frond  arising  from  a  mass  of  rhizoids ;  stipe 
erect,  with  central  layer  of  parallel,  dichotomous  filaments,  and 
distinct  cortical  layer  of  much  narrower,  intricate,  divaricately 
dichotomous  branches  ;  surmounted  by  either  a  distinct  flabellum 
or  a  brush-like  head. 

The  species  with  brush-like  head  resemble  Penicillus,  but  are 
uncalcified  ;  the  flabellate  species  have  the  habit  of  Udotea,  but 
are  distinguished  by  the  more  definite  cortex  of  characteristic 
structure,  as  well  as  by  the  lack  of  calcification. 

KEY  TO  THE  SPECIES  OF  CLADOCEPHALUS. 

i.     With  brush-like  head.  i.     C.  scoparius. 

i.    With  flabellum.  2.     C.  luteo-fuscus. 

i.  C.  SCOPARIUS  Howe,  19053.,  p.  569,  PI.  XXV,  XXVI, 
figs.  11-20;  P.  B.-A.,  No.  1334.  Stipe  2-10  cm.  high,  5-7  mm. 
thick,  cylindrical  or  somewhat  complanate,  often  alate  or  can- 
aliculate above,  sometimes  forked  ;  head  3-8  cm.  long,  brush- 
like,  in  shape  from  linear  or  fusiform  to  obovoid,  more  or  less 
flattened  ;  branches  subcylindrical  or  complanate,  up  to  2  mm. 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  397 

broad,  often  connate;  color  dark  green  to  blackish,  easily  fad- 
ing to  yellowish  ;  filaments  of  medulla  of  stipe  cylindrical  to 
slightly  tornlose,  30-75  //.  diam.  ;  filaments  of  cortex  cylindrical, 
diminishing  in  ultimate  branches  to  6-n  p  diam.  In  quiet 
pools.  Bahama. 

Borgeseu  suggests  that  this  may  be  a  battered  state  of  the  fol- 
lowing species,  but  an  examination  of  a  large  number  of  speci- 
mens of  all  sizes  and  ages  shows  no  indication  of  such  a 
relation. 

2.  C.  LUTEO-FUSCUS  (Crouan)  Borgeseu,  1908,  p.  40,  figs.  7 
and  8;  Udotca  luteo-fusca  Howe,  1907,  p.  513.  Fronds  to  10 
cm.  high,  brownish  ;  stipe  simple  or  1-3  times  dichotomous, 
terete  or  flattened ;  flabellurn  cuneate  to  irregularly  orbicular, 
little  or  not  at  all  zonate,  surface  smooth  or  slightly  rugulose  ; 
filaments  of  medulla  of  stipe  50-80  p  diam.,  the  repeatedly 
dichotomous  branches  forming  the  cortex  diminishing  in  the 
ultimate  divisions  to  4-10  p.  diam.  ;  structure  of  the  flabellum 
similar.  Fig.  151.  W.  I. 

7.  HALIMEDA  L,amouroux,  1812,  p.  186. 
Frond  much  calcified,  consisting  of  more  or  less  flattened 
segments  in  branching  series ;  with  a  more  or  less  distinct 
stem  and  a  mass  of  basal  rhizoids.  A  central  strand  of  inarticu- 
late filaments  passes  through  each  segment,  giving  out  lateral 
branches  whose  terminations  form  the  surface  of  the  segment, 
and  superficially  appear  like  hexagonal  cells.  At  the  apex  of 
each  segment  the  central  filaments  come  into  connection  with 
each  other,  but  separate  when  forming  the  next  segment. 
Fructification  by  globose  or  obovoid  sporangia,  borne  on  the 
margin  or  on  the  face  of  a  segment,  on  branches  from  the  cen- 
tral filaments,  producing  biciliate  spores,  whose  development  is 
unknown. 

The  species  of  Halimeda  are  all  tropical  or  subtropical ;  they 
are  conspicuous  plants,  and  the  Mediterranean  species  was  de- 
scribed over  300  years  ago,  though  it  was  only  in  the  last  cen- 
tury that  it  was  recognized  as  a  plant.  About  20  species  have 
been  described,  based  on  the  external  form  of  the  frond,  but 
this  is  so  variable,  characters  of  several  supposed  species  being 
sometimes  found  on  one  individual,  that  there  has  been  much 
confusion.  By  using  chiefly  Characters  derived  from  the 
central  filaments,  and  from  the  size  and  shape  of  the  ulti- 
mate segments  of  their  branches,  "peripheral  utricles,"  ten 


398     TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

species  can  be  distinguished  in  the  Florida-West  India  region, 
and  fairly  distinct  habit  characters  can  usually  be  found,  but 
doubtful  cases  requiring  decalcification  and  microscopical  exam- 
ination are  not  uncommon. 

KEY  TO  THK  SPECIES  OF  HAIJMEDA. 

i.     Branching  in  more  than  one  plane.  7.     //.  Opunlia. 

i.     Branching  in  one  plane  only  or  with  few  exceptions.  2. 

2.     Peripheral  utricles  cuspidate.  8.     //.  scabra. 

2.     Peripheral  utricles  not  cuspidate.  3. 

3.     All  segments  except  those  bearing  branches  cylindrical. 

2.     //.  Monilc. 

3.     Most  segments  ovoid  or  flattened,  not  cylindrical.  4. 

4.     Peripheral  utricles  over  150  y.  diam. ;  dried  frond  showing  pitted 

surface  when  slightly  magnified.  10.     H.favulosa. 

4.     Peripheral  utricles  not  over  80 /u  diam.  ;  surface  not  pitted.         5. 

5.     Segments  distinctly  ribbed.  i.     //.  tridcns. 

5.     Segments  indistinctly  or  not  at  all  ribbed.  6. 

6.     Segments  slender,  cuueate  to  cylindrical.  3.     PI.  gracilis. 

6.     Segments  broader,  often  broader  than  long.  7. 

7.     Very  slightly  calcified  ;  color  pale.  6.     H.  discoidca. 

7.     More  calcified  ;  color  darker.  8. 

8.     Segments  mostly  with  crenulate,  dentate  or  lobed  margins. 

9.     H.  siniulans. 

8.     Segments  mostly  with  entire  margins.  9. 

9.     Segments  thin,  more  or  less  cuneate,  moderately  calcified. 

5.     H.  Tuna. 
9.     Segments  obovoid,  pyritorm  or  globose,  heavily  calcified. 

4.     H.  lacriniosa. 

i.  H.  TRIDENS  (Ell.  and  Sol.)  L,amouroux,  1812,  p.  186; 
Harvey,  1858,  p.  24,  PI.  XLJV.C.  ;  P.  B.-A.,  No.  1487.  Plants 
up  to  20  cm.  high,  thickly  calcified,  especially  below,  branched 
in  one  plane,  very  variable  in  habit.  Segments  ribbed,  tri- 
dentate,  cuneate  or  discoid,  often  welded  together  near  the 
base  ;  lower  segments  cylindrical,  up  to  8  mm.  diam. ;  tridentate 
segments  up  to  14  mm.  wide.  Filaments  of  central  strand  either 
communicating  with  each  other  at  apex  of  segment  by  pits, 
or  rarely  free  throughout;  peripheral  utricles  49-77  /*  diam., 
rather  loosely  attached,  in  contact  for  one-eighth  to  one- 
twentieth  of  their  length ;  sporangia  obovoid  or  pyriform,  200- 
380 /A  diam.,  color  dark  yellow  or  brown,  on  rather  long,  several 
times  dichotomous  pedicels.  Fla.,  W.  I.  All -warm  seas. 

Forma  typica  (Barton)  nov.  comb.;  //.  incrassata  forma  ly^ica 
Barton,  1901,  p.  27.  Lower  .segments  cylindrical;  upper  seg- 
ments more  or  less  trilobed. 


THE  GRKKN  AI.GAK  OF  NORTH  AMKKICA  399 

Forma  tripartita  (Barton)  nov.  comb.;  //.  incnissnttt  forma 
lrif>tirtita  Barton,  1901,  p.  27,  PI.  IV,  fig.  43.  Lower  segments 
cylindrical;  upper  segments  often  tripartite,  deeply  cut,  divi- 
sions cylindrical. 

A  common  and  variable  species,  of  which  forms  with  broader 
and  tridentate  segments  have  been  known  as  //.  h  ideas,  those 
with  many  cylindrical  segments  as  //.  iticnissata.  Both  forms 
are  found  together  in  Florida  and  the  West  Indies. 

2.  H.  MONILK  Lamouroux,  1812,  p.  186  ;   P.  B.-A.,  No.  1488. 
//.  iticntssata  forma  tnonilis  Barton,  1901,  p.  27,  PI.  IV,  fig.  40. 
Plants  up  to  20  cm.  high,  much  calcified  ;  branching   in  one 
plane  ;  segments  cuneate  or  tridentate  when  bearing  branches, 
all  others  cylindrical,  up  to  8  mm.  long,  1-2  mm.  diam.     Periph- 
eral utricles  30-44 /u  diam.,  adherent  for  one- third  to  one-tenth 
their  length,   not  easily  separable  :  filaments  of  central  strand 
connected  by  pits.     Fla.,  W.  I. 

The  habit  is  usually  quite  distinct  from  that  of  //.  tn'dens, 
with  which  it  has  been  generally  associated  ;  in  occasional 
doubtful  cases,  microscopic  examination  is  needed. 

3.  H.  GRACILIS  Harvey,   Ceylon  Algae,    No.   72 ;   Barton, 
1901,  p.   22,    PI.    Ill,    figs.    28-32;    Vickers,   1908,   p.   24,   PI. 
XXXIV.     Fronds  of  varying  length  up  to  40  cm.,  much  calci- 
fied below,  upper  segments  less  ;  branched  in  one  plane  ;  seg- 
ments  cuneate   to   subcylindrical,  not   ribbed,  l/2-g  mm.  long, 
iJ2-ii   mm.  wide.     Filaments  of  central  strand  fused  in  pairs, 
single  fused  filaments  branching  later  trichotomously  ;  periph- 
eral utricles  30-45  p  diam.     St.  Thomas,  Barbados. 

Reported  from  only  two  localities  within  our  range,  but  likely 
to  be  found  at  other  points.  It  has  probably  been  taken  for  a 
slender,  loosely  branched  H.  Opuntia  or  H.  tridens ;  the  only 
sure  test  would  be  by  microscopic  examination. 

4.  H.  LACRIMOSA  Howe,  1909,  p.  93,  PI.  V,  fig.  i  ;  PI.  VI, 
figs.  3-11.     Plants  up  to  5  cm.  high,  strongly  calcified  ;  branch- 
ing mostly  but  not  exclusively  in  one  plane.     Segments  obovoid, 
pyriform   or  subglobose,  occasionally  subterete,    1-5  mm.  long 
and  broad,  solid  and  stony  or  the  larger  ones  hollow  ;  surface 
smooth  and  compact.     Filaments   of   central   strand    fusing  in 
twos  or  threes  at  the  nodes,  sometimes  with  secondary  incom- 
plete   fusions;    peripheral   utricles   obconical,    40-110  /x   long, 
33-37  M  diam.,  in  contact  for  one-tenth  to  one-thirtieth  of  their 
length;  subcortical  utricles  in  a  single  series,   66- no  /*  diam. 
W.  I. 


400          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

A  species  not  closely  related  to  any  of  the  foregoing  ;  exter- 
nally characterised  by  the  mostly  spherical  or  broadly  pyriform 
segments.  It  appears  to  be  a  plant  of  deeper  water  than  most 
species  of  the  genus. 

5.  H.  TUNA  (Ell.  and  Sol.)  Lamouroux,  1812,  p.  186  ;   ?Har- 
vey,    1858.  p.   25,   PI.  XL. A;    P.  B.-A.,  No.  1484.     Plants  not 
usually  over   10  cm.    long,   moderately  calcified,  branching  in 
one  plane  ;  a  few  of  the  lower  segments  thick,  the  others  thin, 
about   i   mm.,  varying  in  form  but  mostly  cuneate,  not  ribbed, 
margin  entire.     Filaments  of  central  strand  fused  in  twos  or 
threes  at  the  apex  of  each  segment  ;  peripheral  utricles  30-70  p 
diam.,  adherent  for  one-twenty-fifth  to  one-tenth  of  their  length, 
rather  easily  separable  ;    utricles  of   subcortical  layer  35-110/1* 
diam.;    sporangia   globose  to  pyriform,  200-330  /u,  diain.,  deep 
green,  borne  on  simple  or  forked  pedicels,  on  margin  or  surface 
of  the  segments.     Fla.,  W.  I.  Europe,  Asia. 

The  group  including  //.  Tuna,  H.  discoidea  and  H.  scabra  is 
generally  distributed  in  all  warm  waters,  and  distinguished  by 
thin,  not  heavily  calcified  segments.  The  roughened  surface 
distinguishes  H.  scabra,  the  slight  calcification  //.  discoidea. 

6.  H.  DISCOIDEA   Decaisne,  1842,  p.  102  ;  Howe,    1907,   p. 
495,  PI.  XXVI;   P.  B.-A.,  No.  1483.     Plants  reaching  15  cm. 
in  length  and  width,  very  slightly  calcified,  color  bright  green, 
fading  when  dry  ;  branched  in  one  plane  ;  segments  deltoid  to 
elliptical  with  long  axis  transverse,  up  to  35  mm.  broad,  thin, 
smooth,  shining.     Filaments  of  central  strand   fused   in  twos, 
rarely  threes,  at  the  nodes  ;  peripheral   utricles  40-85  p.  diam., 
often   fusing,  in  contact   with  each  other  for  one-fifth  to  two- 
thirds  their  length,  not  easily  separated.     Utricles  of  subcortical 
layer  relatively  large,  bullate,  110-215  A1  diam.     Fla.,  W.  I. 

Asia,  Africa. 

Resembling  H.  Tuna,  but  less  calcified  and  of  thinner  texture  ; 
the  segments  vary  much  in  size,  the  largest  are  broader  than 
long,  and  of  greater  dimensions  than  in  H.  Tuna  ;  in  cases  where 
the  habit  is  not  distinctive  the  shape  and  dimensions  of  the 
utricles  may  be  depended  on  to  decide. 

7.  H.    OPUNTIA    (L.)    Lamouroux,   1812,  p.   186;   Harvey, 
1858,  p.   23,   PI.  XL.B;   Vickers,    1908,  p.  25,  PI.  XXXV;   P. 
B.-A.,  No.   123.     Plants  usually  10  cm.  high,  sometimes  up  to 
25  cm.;  more  or  less  branched  in  various  directions;  segments 
much  calcified,  very  variable  in  shape  ;  discoid,  cordate  or  tri- 
lobed  ;   more  or  less  plainly  ribbed;  up  to  12X20  mm.     Fila- 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  401 

ments  of  central  strand  fused  in  pairs  at  the  apex  of  each  seg- 
ment ;  peripheral  utricles  20-50/01  diam.     Fig.  156.    Fla.,  W.  I. 
Generally  distributed  in  all  warm  waters  ;  forming  dense  tufts, 
by  branching  in  more  than  one  plane. 

8.  H.  SCABRA  Howe,    1905,  p.  241,  Pis.  XI,  XII;   P.  B-A., 
No.   1485.     Frond  up  to  25   cm.  long,  dichotomously,  usually 
much  branched,   always  in  one  plane  ;  segments  strongly  cal- 
cified, not  ribbed,   reniform,  suborbicular,  occasionally  deltoid- 
obovate,    up    to    14   mm.    broad,    1.5  mm.  thick;    filaments  of 
central  strand  fused  in  twos  and  threes  at  the  joints  ;  peripheral 
utricles  27-50  p.  diam.,  each  prolonged  into  an  acuminate,  often 
indurated   terminal  cusp  ;    in  contact  for   onljr  a  small  portion 
of   their  length,  rather   easily  separated  ;    sporangia  pyriform, 
160-320  n  diam.,   usually  distichously  arranged  on  simple  or 
forked  pedicels,  covering  the  margin,  rarely  the  disk  of  a  seg- 
ment.    Fla.,  W.  I. 

This  species  has  passed  under  the  name  of  //.  Tuna,  but  is 
amply  distinct  by  the  cuspidate  peripheral  utricles,  which  are 
visible  under  a  good  lens,  and  give  a  rougher  feeling  to  the  plant 
than  is  found  in  the  smooth-utricled  H.  Tuna.  The  material 
distributed  as  P.  B.-A.,  No.  167,  is  partly  this  species,  partly 
//.  discoidea. 

9.  H.  SIMULANS  Howe,  1907,  p.  503,  PI.  XXIX;  P.  B.-A., 
No.  1486.     Plant  up  to  15  cm.  high,  strongly  calcified,  flabel- 
late  in  outline,  branching  in  one  plane  ;  segments  discoid,  plane 
or  somewhat    i-3-nerved,    subquadrate  to  obovate  in  outline, 
usually  broader  than  long,  margin  entire,  crenulate,  dentate  or 
lobed  ;  up  to  12  mm.  wide,  to  2  mm.  thick  ;  peripheral  utricles 
33-40  n  diam.,  in  contact  one-third  to  one-tenth  of  their  length, 
rather  firmly  adhering.     Filaments  of  the  central  strand  coher- 
ent at  the  nodes,  connecting  by  open  pits  or  very  short  tubes. 
W.  I. 

Individuals  of  this  species  often  resemble  H.  Tuna  or  //.  tri- 
dens  in  some  habit  characters,  but  it  is  seldom  that  there  is 
doubt  on  considering  all  the  characters. 

10.  H.  FAVULOSA  Howe,    19053,  p.  563,   PI.  XXIII,  fig.  2  ; 
PI.  XXVI,  figs.  1-6.     Fronds  up  to  20  cm.  high,  rather  thickly 
calcified,   branching  densely  in  one  plane  ;    segments  varying 
much  in  form,  cylindrical  to  trilobed  or  discoid,  up  to  9  mm. 
long  and  broad,  and  2  mm.  thick.     Filaments  of  central  strand 
connected    at   the  joints   by  very   short   processes ;    peripheral 
utricles  110-260 /x  across.     Bahama. 


402  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

In  habit  much  like  H.  tridens,  but  readily  distinguished  by 
the  large  peripheral  utricles,  easily  seen  with  slight  magnifica- 
tion. In  dried  plants  they  collapse,  the  calcareous  framework 
resembling  a  honeycomb  ;  the  surface  of  H.  tridens  seems  quite 
smooth  unless  considerably  magnified. 

Family  2.     BRYOPSIDACEAE. 

Vegetative  frond  unicellular,  much  branched  ;  chromatophores 
numerous  small  disks,  each  with  one  pyrenoid  ;  the  axis  pro- 
ducing below  rhizoids,  and  above  branches  both  of  unlimited 
and  limited  growth ;  in  the  latter  large  biciliate,  green,  female 
gametes,  and  on  separate  individuals,  smaller, .brown,  biciliate 
male  gametes  are  formed  ;  by  the  union  of  the  two  a  zygote  is 
formed,  germinating  immediately.  Only  one  genus  with  us. 

BRYOPSIS  Lamouroux,  1809,  p.  129. 
Characters  of  the  family  ;  marine. 

A  genus  mostly  of  warm  waters,  some  few  species  extending 
into  and  throughout  the  temperate  zone ;  mostly  attractive 
plants  with  symmetrical  form,  glassy  membrane  and  rich  color. 
The  forms  of  our  region  group  themselves  around  two  types  : 
B.  plumosa  with  firm,  distichous  ramuli,  not  much  smaller  than 
the  branch  from  which  they  issue  ;  B.  hypnoides  with  more 
flaccid  ramuli,  not  distichous,  generally  more  slender  than  the 
branch  from  which  they  issue.  Whether  our  forms  should  all 
be  considered  as  varieties  of  these  two  species,  or  whether  we 
have  a  number  of  distinct  species,  as  given  below,  can  be  de- 
termined only  by  careful  study  of  living  plants. 

KEY  TO  THE  SPECIES  OF  BRYOPSIS. 

i.     Ramuli  not  distichous.  2. 

i.     Ramuli  distichous,  generally  unbranched.  4. 

2.     Ramuli  long,  not  distinct  in  character  from  the  branch  bearing 

them.  i.     B.  hypnoides. 

2.     Ramuli  short.  3. 

3.     Ramuli  forming  a  dense  coating  on  the  stouter,  virgate  branches. 

2.     B.  Duchassaingii. 
3.     Ramuli  scattered,  alternate,  or  in  short,  secund  series. 

5.     B.  ramulosa. 
4.     Corticating    rhizoidal    filaments    abundant    at    the    base    of    the 

branches  and  ramuli.  4.     B.  corticulans. 

4.     Corticating  filaments  inconspicuous.  5. 

5.     Ramuli  in  short,  subdistant  series.  6.     B '.  Leprieurii. 

5.     Ramuli  mostly  in  one  continuous  series.  6. 


THE  GREEN  ALGAE  OK  NORTH  AMERICA  403 

6.     Ramuli  forming  a  distichous  plumule.  7. 

6.     Ramuli  forming  an  apparently  secund  plumule.  8. 

7.     Plumule  linear  to  linear-lanceolate;  stems  seldom  branched. 

7.     B.pennata. 
7.     Plumule  usually  triangular  ;  stems  generally  freely  branched. 

3.     B.  plumosa. 
8.     Ramuli  forming  a  plumule  over  all  but  the  base  of  the  rachis. 

9.     B.  foliosa. 
8.     Ramuli  iu  a  short  series  below  the  naked,  often  incurved  tip. 

8.     B.  Harveyana. 

1.  B.  HYPNOIDES  Lamouroux,    1809,  p.  135,  PI.  I,  fig.  2,  a 
and  b;   Harvey,  1846-51,  PI.  CXIX  ;   Vickers,    1908,  p.  30,  PI. 
IvIII  ;   P.  B.-A.,  Nos.  1028,  1286;  not  474.     Frond  seldom  over 
10  cm.  high,  soft,  rather  pale  green,  usually  much  branched, 
branches  in  no  definite  order,  growing  smaller  in  the  successive 
series,  and  with  no  sharp  division  between  the  lesser  branches 
and  the  ramuli  that  clothe  them  on  all  sides,  and  themselves 
branch  more  or  less.     Southern  Mass,  to  W.  I.  ;  Washington  to 
southern  Cal.  I  Europe. 

A  common  European  species,  considered  rare  on  our  Atlantic 
coast,  but  probably  often  mistaken  for  B.  plumosa.  There  is 
little  distinction  between  the  various  orders  of  branches,  and 
though  the  plant  is  delicate  and  graceful,  there  are  none  of  the 
definite  plumules  characteristic  of  B.  plumosa  and  its  allies. 

2.  B.  DUCHASSAINGII  J.  G.  Agardh,  1854,  p.  107;   1886,  p. 
31  ;  B.  hypnoidcs  P.  B.-A.,  No.  474,  not  1028,  1286  ;    Trichosolen 
antillarum  Montagne,  1860,  p.  171,  PI.  XI. C.     Frond  up  to  20 
cm.  high,  rather  pale  green  ;  stem  stout,  main  branches  long, 
virgate,  with  one  or  more  series  of  similar  branches,  covered  in 
the   upper  part  with  a  woolly  coating  of  short  ramuli,  shorter 
towards  the  end  of  the  branch,  giving  the  branch  a  linear  or 
linear-lanceolate  outline  with  acute  tip ;  also  with  numerous 
short,  slender,  secondary  branches,  bare  below,  the  upper  part 
densely  covered  with  minute  ramuli.     Fla.,  W.  I. 

The  main  stems  are  stouter  than  in  B.  hypnoidcs,  the  ramuli 
are  shorter  and  denser,  the  branches  virgate  and  not  much 
divided.  The  branches  vary  much  in  length,  and  the  frond 
does  not  have  the  regular  outline  usually  found  in  most  species 
of  Bryopsis. 

3.  B.  PLUMOSA    (Huds.)    Agardh,    1822,    p.    448;    Harvey 
1846-51,  PI.  Ill ;   1858,  p.  31  ;  Farlow,  1881,  p.  59,  PI.  IV,  fig. 
i  ;  P.  B.-A.,  No.  227.     Frond  seldom  over  10  cm.  high,  rich 
and  glossy  green  ;  amount  of  branching  variable  ;  typical  forms 


404          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

with  numerous  lateral  branches  and  often  a  second  series ;  all 
branches  with  abundant  distichous  ramuli,  shorter  above,  giv- 
ing the  branches  a  triangular  outline.  Fig.  155.  Me.  to  Fla. 

En  rope. 

The  best  known  and  most  widely  distributed  species  of  the 
genus,  and  to  which  may  possibly  be  referred,  as  forms,  quite  a 
number  of  less  familiar  species,  so  now  regarded.  It  is  no- 
where very  abundant,  but  occurs  in  various  stations  ;  rocky  tide 
pools,  muddy  shores,  wood  work  of  wharves,  etc.  In  its  north- 
ern range  it  seems  to  be  more  specially  a  summer  plant,  but  is 
sometimes  found  at  any  season. 

4.  B.    CORTICULANS  Setchell,    P.  B.-A.,    No.    626.     Frond 
rather  stout  and  coarse,  up  to  20  cm.  high,  dark  green  in  the 
growhig    parts,    glossy   throughout ;     main    stems     not     much 
divided,  lower  part  naked,  upper  part,  usually  about  half  of 
the  whole   length,   with    abundant   patent,    generally    opposite 
branches,    naked    b.elow,    above  with  'rather   stout,   distichous 
ramuli,   decreasing  in  length  towards  the  tip   of   the   branch  ; 
general  outline  of  frond  and  of  individual  branches  pyramidal  ; 
conspicuous  tufts  of  descending  rhizoidal  filaments  found  at  the 
bases  of  the  branches.     Vancouver  to  Cal. 

Resembling  B.  plumosa,  under  which  name  the  distichously 
branched  plant  of  the  Pacific  coast  has  usually  been  distributed  ; 
but  it  is  a  larger  and  coarser  plant  than  the  B.  plumosa  of  the 
Atlantic,  and  the  corticating  filaments  are  much  developed,  not 
exceptional  as  in  B.  plumosa.  Unfortunately,  these  differences 
are  of  the  same  character  as  are  often  found  between  Atlantic 
and  Pacific  forms  of  what  passes  for  the  same  species  ;  whether 
they  are  of  specific  importance'  in  this  case  can  hardly  be  deter- 
mined at  present. 

5.  B.  RAMULOSA  Montague,  18383,  p.  16,  PI.  Ill,  fig.  2  ;  B. 
plumosa  var.  ramulosa  Harvey,  1858,   p.   31,   PI.   XLV.A.,  figs. 
4-6.     Fronds  densely  tufted,  little  branched,  rather  coarse,  dark 
green  ;  ramuli  uniformly  short,  scattered,  in  longer  or  shorter 
secund  series,  or  in  occasional   opposite  pairs  ;  mostly  in  the 
middle  of  the  filament,  seldom  in  the  lower  part  or  at  the  tip. 
Fla.,  W.  I. 

Ramuli  very  short  and  inconspicuous,  so  that  the  fronds  seem 
like  depauperate  or  denuded  specimens  of  some  other  species. 

6.  B.  LEPRIEURII  Kiitzing,  1849,  p.  490;   1856,  PI.  L,XXV, 
fig.  2  ;  Vickers,  1908,  p.  29,  PL  L,.     Fronds  up  to  15  cm.  high, 


THK  GRKEN  AI.C.AK  OK  NORTH  AMERICA  405 

rather  sparingly  branched,  often  undulately  curved  and  swollen 
i:i  places  ;  ramuli  rather  short,  blunt,  in  se'cund  series  of  a  few 
each,  the  rachis  naked  between  the  series.  \V.  I. 

So.  America . 

The  four  species,  B.  fo/iosa,  B.  pennata,  />.  Lepricurii  and 
/.'.  HarvcyiDia  are  certainly  closely  related ;  only  continued 
study  of  the  living  plants  will  settle  -the  question  of  their  dis- 
tinctness. That  the  three  last  named  are  kept  separate  here  is 
chiefly  due  to  their  being  so  kept  by  Miss  Vickers,  who  studied 
and  collected  them  at  Barbados. 

7.  B.  PKXNATA   L,amouroux,    1809,  p.    134,    PI.   Ill,  fig.  i  ; 
Vickers,    1908,   p.   30,    PI.   UI ;  B.  pennatula  J.   G.   Agardh, 
1848,  p.  6.     Fronds  seldom  over  5  cm.  high,  tufted,  simple  or 
nearly    so,    bearing,    except    at    the   very    base,    rather   short, 
densely  set,  distichous  ramuli  of  uniform  length,  giving  a  linear 
outline  to  the  frond.     W.  I.,  Mexico. 

The  narrow  subsimple  frond  reminds  one  of  the  European  B. 
my  lira  ;  but  the  distichous  ramuli  place  it  near  B.  plumosa. 

8.  B.  HARVEYANA  J.  G.  Agardh,    1886,    p.    22 ;    Vickers, 
1908,  p.  29,  PI.  LI ;   P.  B.-A.,  No.  1532  ;  B.  plumosa  var.  secunda 
Harvey,    1858,  p.  31,   PI.  XLV.A,  figs.  1-3.     Fronds  up  to   15 
cm.  high,  dark  green,  growing  in  dense  tufts  ;  main  stems  mod- 
erately and  rather  irregularly  branched,  branches  bearing  near 
the  end  rather  short,  distichous  ramuli,  the  general  outline  be- 
ing linear-lanceolate,   or  linear  with  rounded  ends,  the  tip  of 
the  branch  somewhat  prolonged.     This  tip  is  usually  somewhat 
incurved,  and  the  ramuli  on  both  edges  of  the  rachis  turn  in- 
wards towards  one  side  of  the  latter,  so  that  unless  closely  ex- 
amined they  appear  secund.     Fla.,  W.  I. 

The  characters  by  which  this  is  distinguished  from  B.  plu- 
mosa are  not  as  sharp  nor  as  constant  as  might  be  wished  ;  but 
well  developed  plants  seem  quite  distinct  by  their  densely  tufted, 
little  branched  fronds,  each  filament  with  scorpioidal-appearing 
tip. 

9.  B.   EOLIOSA  Sender,    1845,   p.   49.     Frond  2-3  cm.  high, 
ascending  from  more  or  less  abundant  creeping  filaments  ;  usu- 
ally simple,  occasionally  once   or   twice    forked,   tip   somewhat 
incurved,  base  naked,  but  with  scars  of  fallen  ramuli ;  upper 
part    thickly  set   with    ramuli,    arising   dichotomously  on   the 
rachis,  but  curving  immediately,   and  all  turned  in  the  same  di- 
rection, so  as  to  appear  secund  on  the  outer,  convex,  side  of  the 
rachis  ;  ramuli  slender,  patent,  the  lowest  longest,  up  to  5  mm., 


406          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

generally  simple,  occasionally  with  a  few  rudimentary  ramelli. 
Guadeloupe.  Australia. 

The  ramuli  in  this  species  originate  in  the  same  way  as  in  B. 
plumosa,  but  instead  of  continuing  the  distichous  arrangement, 
both  series  bend  towards  the  same  side,  until  their  direction  is 
the  same,  and  the  branching  appears  secund.  B.  Harveyana 
has  the  same  branching,  b'ut  the  ramuli  are  stouter,  and  instead 
of  forming  a  definite  plumule  over  all  but  the  base  of  the  rachis, 
occur  in  short  series,  below  the  naked  tip.  This  species  is  here 
included  from  the  reference  in  Agardh,  1886,  p.  26,  and  the  de- 
scription there  given  is  copied  ;  the  original  description  by  Son- 
der  is  very  meager  ;  it  is  not  clear  just  how  it  is  to  be  distin- 
guished from  forms  of  B.  Harveyana. 

Family  3.     DERBESIACEAE. 

Frond  filiform,  unicellular  or  with  occasional  partitions,  mul- 
tinucleate,  simple  or  branched,  with  no  differentiation  of  axis 
and  branches  ;  chromatophores  numerous  disks,  with  or  with- 
out pyrenoids  ;  asexual  reproduction  by  large,  multiciliate  /oo- 
spores,  each  with  one  nucleus,  formed  in  lateral  cells  partitioned 
off  from  the  filaments.  Only  one  genus. 

DERBESIA  Solier,  1847,  p.  158. 
Characters  of  the  family.     Marine. 

KEY  TO  THE  SPECIES  OF  DERBESIA. 

I.     Filaments  100-600  /u.  diarn.  3.     D.  Lamourouxii. 

i.     Filaments  less  than  100  n  diam.  2. 

2.     Branching  mainly  dichotomous  ;  pedicel  of  sporangium  about  15  M 

diam.  i.     D.  vaucheriaefonnis. 

2.     Branching  mainly  lateral ;  pedicel  25-35 /x  diam.     2.    D.  marina. 

i.  D.  VAUCHERIAEFORMIS  (Harv.)  J.  G.  Agardh,  1886,  p. 
34;  P.  B.-A.,  No.  318;  D.  tenuissima  Farlow,  1881,  p.  60,  PI. 
IV,  fig.  4;  Chlorodesmis  vaucheriaefonnis  Harvey,  1858,  p.  30, 
PL  XL.D.  Filaments  erect,  40-50  //.  diam.,  dichotomously 
branched,  up  to  4-5  cm.  high,  in  dense  fastigiate  tufts  ;  on  one 
or  both  branches,  a  short  distance  above  the  forking,  two  parti- 
tions are  often  formed,  the  space  between  being  30-35  ^  in 
length,  and  about  the  same  diam.  Sporangium  formed  in  the 
place  of  a  branch,  ovoid  or  broadly  pyriform,  i9o-3ooX  100-130  /x, 
supported  by  a  slender  pedicel,  about  15  ^  diam.,  50-100  p.  long, 
in  which  two  partitions,  similar  to  those  at  the  base  of  a  branch, 
enclose  a  cell  2-4  times  as  long  as  broad;  spores  large,  about  15 
in  a  sporangium.  Southern  Mass.,  Fla. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  407 

In  appearance  not  unlike  a  Vaucheria,  but  of  more  erect  habit, 
and  lacking  the  elaborate  sexual  apparatus  of  that  genus. 

2.  D.  MARINA  (Lyng.)  Kjellman,    1883,   p.  316;  D.  temiis- 
sinia  P.  B.-A.,  No.  574.*     Arising  from  a  more  or  less  distinctly 
developed   layer  of   irregular   creeping  cells ;    erect   filaments 
bright  green,  50-70  ^  diam.,  sometimes  simple  but  usually  with 
a  few  lateral  branches  similar  to  the  axis  ;  a  cell  partitioned  off 
frequently  near  the  base  of  a  branch,  and  occasionally  in  the 
axis   just  above  a  branch,  not  much  smaller  than  the  branch, 
about  as  long  as  broad  ;  sporangium  occupying  the  place  of  a 
branch,  150-250X90-200 /A,  from  obovoid  to  subspherical ;  pedi- 
cel varying  from  30-70  p  in  length,  30-35  p.  diam.,  the  cell  formed 
in  it  being  about  as  long  as  broad  ;  spores  20  or  more  in  a  spor- 
angium.    Fig.  152.     Alaska  to  Southern  Cal.  Europe. 

3.  D.  LAMOUROUXII  (J.  Ag.)  Solier,   1847,   p.   162,  PI.  IX, 
figs.    18-30;    Bryopsis   simplex    Rabenhorst,    Algen,    No.   916. 
Filaments  arising    from  a  creeping  base,  from  a  few  cm.  to  2 
dm.  high,    100-600  /*  diam.,  dark  green,  rather  stiff,  sometimes 
simple,    sometimes    with    more    or    less    numerous    irregular 
branches;  sporangia  globose,  300-550  //.  diam.,  sessile  or  on  a 
short  and  slender  pedicel.     Southern  Cal.  Europe. 

Distinguished  from  our  other  species  by  the  much  larger  fila- 
ments. Only  sterile  plants  have  yet  been  found  here,  and 
though  they  agree  very  well  with  the  Mediterranean  plant,  the 
identification  is  uncertain  until  fruit  is  observed. 

Family  4.     PHYLLOSIPHONACEAE. 

Frond  filiform,  inarticulate,  branching  ;  perforating  the  shells 
of  tnollusks,  or  parasitic  in  the  tissues  of  plants  ;  asexual  repro- 
duction, known  only  in  one  genus,  by  aplanospores. 

The  family  was  founded  on  the  genus  Phyllosiphon  ;  the  in- 
clusion of  Ostrcobium,  so  totally  different  in  its  habitat,  may  seem 
hardly  warranted  ;  but  the  two  resemble  each  other  in  the  form 
of  the  vegetative  frond  more  than  they  do  any  other  genus  ;  the 
reproduction  of  Ostreobium  being  quite  unknown,  the  present 
place  is  as  suitable  as  any  for  it,  temporarily. 

KEY  TO  THE  GENERA  OF  PHYLLOSIPHONACEAE. 

i.     Parasitic  in  the  tissues  of  plants.  i.     PHYLLOSIPHON. 

i.     Perforating  the  shells  of  tnollusks.  2.     OSTREOBIUM. 

*  D.  tenuissima  (De  Not.)  Crouan,  of  southern  Europe,  has  sporangia 
sessile,  without  the  short  cell. 


408          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

i.     PHYLLOSIPHON  Kiihn,  1878,  p.  32. 

Parasitic  in  the  leaves  and  stems  of  flowering  plants  ;  ends  of 
the  filaments  and  their  branches  without  chlorophyll,  lower 
parts  with  chlorophyll,  but  with  little  indication  of  definite 
chromatophores ;  asexual  reproduction  by  aplanospores,  with 
distinct  parietal  chromatophore,  escaping  by  rupture  of  cell 
wall. 

P.  ARISARI  Kiihn,  1878,  p.  32;  Just,  1882;  p.  i,  PI.  I;  P. 
B.-A.,  No.  1285.  Filaments  25-35  P-  diam.,  during  spore  form- 
ation up  to  60  /A  diam.-,  irregularly  or  dichotomously  branched, 
creeping  between  the  cells  in  the  parenchyma  of  the  leaf  or 
petiole  of  the  host  plant ;  forming  larger  or  smaller  yellowish 
patches,  up  to  several  cm.  diam.,  each  patch  formed  of  a  single 
individual  ;  aplanospores  formed  in  great  numbers,  ovoid,  about 
5X2. 5  p.;  development  unknown.  Fig.  [57.  N.  H.  Europe. 

In  Europe  this  plant  infests  Arisarum  vulgare ;  here  the 
nearly  allied  Arisaema  triphyllum.  In  spite  of  its  abundant 
chlorophyll  it  appears  to  be  a  true  parasite,  drawing  its  supplies 
from  the  cells  of  the  host  plant,  which  it  ultimately  exhausts  ; 
but  it  does  not  penetrate  the  cells,  nor  are  there  any  specialized 
haustoria. 

2.     OSTREOBIUM  Bomet  and  Flahault,  1889,  p.  CL,XIII. 
Fronds  tubular,  branched,  with  occasional  swellings  ;  living 
in  the  shells  of  mollusks  ;  reproduction  unknown. 

O.  QUEKETTII  Bornet  and  Flahault,  1889,  p.  CIvXIII,  PI.  IX, 
figs.  5-8.  Fronds  slender,  in  main  divisions  4-5  /x  diam.,  with 
numerous  lateral,  divaricate  branches,  which  by  repeated 
branching  form  a  close  network,  the  ultimate  divisions  about 
2  /A  diam.  ;  occasional  irregular  swellings  in  the  filaments,  20-40 
/u,  diam.  In  old  shells  of  oysters  and  other  mollusks.  Fig.  159. 
Mass.,  Conn.  J^urope. 

This  species  often  grows  in  company  with  Gomontia  polyrhiza, 
from  which  it  is  easily  distinguished  by  the  continuous,  not 
cellular  filaments ;  the  swellings  would  seem  to  indicate  repro- 
ductive organs  of  some  sort,  but  nothing  has  been  found  in  them 
different  from  the  contents  of  the  more  slender  parts. 

Family  5.     CAULERPACEAE. 

Frond  tubular,  multinucleate,  unicellular,  traversed  by  cross 
strands  of  cellulose.  Reproduction  by  division  of  the  frond  ;  no 
other  method  known.  Containing  only  one  genus. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  409 

CAULERPA  Lamouroux,  18093,  p.  30. 

Frond  composed  of  a  creeping  stolon  (wanting  in  one  species), 
giving  out  rhizoids  below  and  branches  above.  The  latter  of 
various  form,  usually  erect,  but  sometimes  prostrate  ;  simple  or 
branched.  Marine. 

A  remarkable  genus,  of  many  species  of  very  diverse  shape 
and  degree  of  vegetative  differentiation,  but  all  constructed  on 
the  type  of  a  creeping  rhizome-like  stem,  giving  out  filamentous 
rhizoids  below,  and  erect  branches  above.  For  the  latter  the 
word  "  frond  "  will  be  used  in  the  following  pages,  in  a  special 
limited  sense.  These  fronds  vary  from  the  simplest  filaments  to 
very  elaborate  branching  structures,  often  simulating  to  a  sur- 
prising degree  the  forms  of  higher  plants,  so  that  most  of  the 
sections  of  the  genus  are  named  for  these  resemblances,  and 
these  names  often  give  as  good  an  idea  of  the  habit  as  can  be 
obtained  from  technical  descriptions.  The  entire  plant,  how- 
ever differentiated,  is  continuous  throughout,  not  divided  into 
cells,  and  the  only  propagation  known  is  by  the  breaking  off 
from  the  frond  of  some  part,  which  continues  to  grow  as  a  dis- 
tinct individual.  Pieces  of  either  rhizome  or  frond  can  de- 
velop in  this  way,  so  that,  in  one  sense,  all  the  plants  on  a 
whole  stretch  of  coast  may  be  a  single  individual,  broken  up  by 
various  causes. 

While  very  various  types  of  form  are  found  in  various  species, 
the  lines  cannot  be  sharply  drawn,  one  form  passing  insensibly 
into  another.  Being  tropical  or  subtropical  plants,  much  the 
greater  part  of  the  species  have  been  founded  on  dried  speci- 
mens only,  often  very  fragmentary  and  insufficient  specimens, 
obtained  by  collectors  by  no  means  specialists  in  algae.  Thus 
it  has  frequently  happened  that  species  have  been  founded  on 
specimens  showing  markedly  different  characters,  while  later 
investigation  has  brought  to  light  plants  with  fronds  of  both 
types  growing  from  the  same  stem. 

The  careful  revision  of  the  genus  by  Mme.  Weber  van  Bosse, 
1898,  founded  largely  on  the  study  of  living  plants  and  by  com- 
parison of  practically  all  the  original  specimens,  has  been  fol- 
lowed in  the  following  descriptions.  Many  varieties  and  forms 
are  given  in  her  work,  corresponding  largely  to  former  species, 


410          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

but  with  the  note  that  too  much  stress  should  not  be  laid  on 
them,  except  as  indicating  special  lines  or  limits  of  variation. 
A  short  characterization  of  all  the  sections  is  given  below,  but 
three  sections  are  not  yet  represented  in  North  America  :  Sect. 
4,  Zosteroideae,  Africa  and  Spain  ;  Sects.  7  and  10,  Hippuroideae 
and  Araucarioideae,  Australia. 

SECTIONS  OF  CAULERPA. 

I.  Stolon  and  erect  fronds  filiform,  without  differentiated  ramuli. 

i.    VAUCHERIOIDEAE. 

II.  Stolon  cylindrical  and    creeping;    erect  fronds   of    distinct  ]jforrn. 
Stolon  naked  or  with  simple  or  bifid  hairs  ;  fronds  slender,  bearing 

near  the  summit  whorled  ramuli.  2.         CHAROIDEAE. 

Stolon  with  hairs  or  ramuli;  frond  of  a  moss-like  aspect,  surrounded 
by  more  or  less  branching  ramuli.  3.  BRYOIDEAE. 

Stolon  naked  ;  fronds  elongate  in  the  form  of  a  Zostera  leaf,  flat  or 
cylindrical,  simple  or  dichotomous ;  margin  entire,  without 
ramuli.  4.  ZOSTEROIDEAE. 

Stolon  naked ;  fronds  flat,  margin  entire  or  slightly  serrate,  little 
branched,  but  often  producing  proliferously  from  the  lamina 
similar  secondary  laminae.  5.  PHYLLANTOIDEAE. 

Stolon  naked  ;  fronds  flat,  deeply  dentate,  serrate  or  pinnate,  rarely 
cylindrical,  and  then  surrounded  by  pinnules  several  times 
as  long  as  the  diameter  of  the  axis.  6.  FIUCOIDEAE. 

Stolon  naked  or  with  scattered  ramuli ;  fronds  simple  or  branched, 
surrounded  by  three  or  more  ranks  of  imbricate  spreading  or 
erect  ramuli ;  ramuli  sometimes  short,  usually  long,  simple, 
forked,  or  pinnate.  7.  HIPPUROIDEAE. 

Stolon  covered  with  woolly  hairs  or  simple  ramuli ;  fronds  cylindrical, 
simple  or  branched,  surrounded  by  very  densely  set  simple 
or  bifid  ramuli.  8.  LYCOPODIOIDEAE. 

Stolon  naked;  fronds  generally  robust,  but  sometimes  slender,  fas- 
tigiate,  cylindrical,  surrounded  by  cylindrical,  ovoid  or 
pyramidal  ramuli,  distichous,  tristichous  or  multiseriate  ; 
or  sometimes  plane  and  linear  with  edges  entire,  dentate  or 
serrate,  twisted  or  not.  9.  THUYOIDEAE. 

Stolon  covered  with  four-parted  scales ;  fronds  resembling  an  Arau- 
caria,  with  branches  distichous,  sub-opposite  or  alternate, 
covered  with  simple  or  bifid,  mucronate  ramuli. 

10.    ARAUCARIOIDEAE. 

Stolon  naked ;  frond  of  a  primary  naked,  simple  or  dichotomous 
axis,  bearing  at  its  summit  simple  or  dichotomous  secondary 
axes,  bearing  pinnate  ramuli.  Pinnules  usually  unilateral, 
turned  upwards,  simple  or  pinnate,  mucronate. 

ii.    PASPALOIDEAE. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  411 

Stolon  naked;  fronds  simple  or  branched,  terete  or  annulate,  bear- 
ing distichous  or  tnultiseriate,  ovoid,  clavate,  cylindrical  or 
linear,  sessile  or  pedicellate  ramuli.  12.  SEUOIDEAE. 

KEY  TO  THE  SPECIES  OK  CAULERPA. 

i.     Stolon  wanting.  16.     C.  ambigua. 

I.     Stolon  present.  2. 

2.     Stolons  and  fronds  filiform,  without  distinct  ramuli. 

i.     C.  fastigiata. 

2.     Stolons  and  fronds  different  in  character.  3. 

3.     Fronds  very  slender,  ramuli  whorled,  near  the  summit.  4. 

3.     Fronds  stouter,  ramuli  not  in  distinct,  distant  whorls.  5. 

4.     Not  over  i  cm.  high  ;  stolon  and  base  of  fronds  hairy. 

2.     C.  pus  ilia. 

4.     Up  to  5  cm.  high  ;  hairs  wanting  or  few.  3.     C.  verticillata, 

5.     Stolons  naked.  6. 

5.     Stolons  with  hairs  or  ramuli.  13. 

6.     Fronds  flat.  7. 

6.     Fronds  terete  or  compressed.  n. 

7.     Margin  entire.  5.     C.  prolifcra. 

7.     Frond  pinnate,  with  linear-lanceolate  outline.  8. 

7.     Frond   narrowly  linear,  more  or  less   twisted,  with   frequent  con- 
strictions, ii.     C.  Freycinetii. 

8.     Pinnules  flat.  6.     C.  crassifolia. 

8.     Pinnules  cylindrical  or  compressed.  9. 

9.     Pinnules  terete,  tip  obtuse,  somewhat  clavate.       8.     C.  Ashmeadi. 
9.     Pinnules  mucronate  or  tapering  at  tip.  10. 

10.     Pinnules  narrowed  at  base  and  tapering  to  tip.     7.     C.  taxifolia. 

10.     Pinnules  at  base  somewhat  larger  than  the  curved  and  mucronate 
tip.  9.     C.  sertular aides. 

ii.     Frond  with  naked  primary  axis  and  ramelliferous  secondary  axes. 

13.     C.  paspaloides. 
ii.     Frond  without  distinction  in  character  between  axes  of  different 

orders.  I2- 

12.     Frond  beset  with  ramuli  varying  from  long-clavate  to  spherical- 
pedicellate.  14-     C.  racemosa. 
12.     Frond  with  peltate  ramuli.  15-     C.  peltata. 
12.     Frond  more  or  less  angled,  with  short  ramuli  of  varying  forms, 

the  lowest  always  "  rostriform."  12.     C.  cupressoides. 

13.     Fronds  beset  with  more  or  less  densely  branching  ramuli. 

4.     C.  Webbiana. 
13.     Fronds  beset  with  very  densely  set  simple  or  bifid  ramuli. 

10.     C.  Lycopodinni. 

i.     C.  FASTIGIATA  Montague,  18383,  p.    19,   PI.  II,  fig.  3; 
Weber,  1898,  p.  262,  PI.  XX,   figs,  i  and  2  ;  Vickers,   1908,  p. 


412  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

25,  PI.  XXXVI ;  P.  B.-A.,  No.  1078.  Stolon  creeping,  naked; 
fronds  ascending,  numerous,  branching  alternate,  dichotomous, 
or  opposite  ;  ramuli  fastigiate,  issuing  at  rounded  angles,  cylin- 
drical, long,  obtuse,  sometimes  shorter  and  slightly  clavate. 
Fla.,  W.  I.  Brazil. 

A  Vaucheria-like  plant  growing  in  tufts  or  turfs  at  low  water 
mark.  It  would  hardly  be  taken  for  a  Caulerpa  by  one  familiar 
with  only  the  more  elaborate  forms. 

Var.  CONFERVOIDES  Crouan  in  Maze  and  Schramm,  1870-77, 
p.  83.  Stolon  floating,  emitting  loose,  floating  fronds,  10  cm. 
long.  Fla.,  W.  I. 

Differs  from  the  type  only  in  habit.  P.  B.-A.,  No.  1078  seems 
to  belong  to  this  variety  rather  than  to  the  type. 

2.  C.  PUSILLA  (Kiitz.)  J.    G.   Agardh,    1872,    p.   6;   Weber, 
1898,  p.  266,  PI.  XX,  fig.  6  ;  Vickers,  1908,  p.  25,  PI.  XXXVIII. 
Stolon  covered  with  bifid,   hyaline   hairs,   which  attach  them- 
selves to  the  substratum  ;  fronds  erect,  up  to  i  cm.  high,  at  the 
base  surrounded   by  hyaline  hairs,  once  or  twice  forked,  and 
bearing  near  the  top  two  or  three  successive  tufts  of  whorled,  di- 
or  trichotomous,  fastigiate,  mucronate  ramuli.     Barbados. 

So.  America. 

3.  C.  VERTiciLLATA   J.   G.    Agardh,    1848,    p.    6;  Weber, 
1898,  p.  267,   PI.  XX,   figs.  7-10 ;  P.  B.-A.,   No.  665.     Stolon 
creeping,  with  few  hairs ;  frond  repeatedly  branched,  up  to  3-4 
cm.  high,  filiform,  bearing  at  the  summit  successive  series  of 
two  or  more  whorls  of  ramuli,  two  to  many  ramuli  in  a  whorl ; 
ramuli   fastigiate  or  nearly  so,    sometimes  spread  out  in  fan- 
shape,  di-  or  trichotomous.     W.  I.        Indian  and  Pacific  Oceans. 

Resembling  C.  pusilla,  but  a  larger  plant,  and  with  few  or 
none  of  the  hairs  characteristic  of  the  latter. 

Forma  CHAROIDES  (Harv.)  Weber,  1898,  p.  267  ;  Borgesen, 
1907,  p.  356,  fig.  2.  Frond  bearing  at  the  summit  alternate  or 
opposite,  scattered  ramuli,  not  arranged  in  series  of  whorls. 
Cuba,  St.  Croix.  Pacific. 

4.  C.  WEBBIANA  Montagne,  1840,  p.  129;  Weber,  1898,  p. 
269,  PI.  XXI,  figs.  1-4;  P.  B.-A.,  No.  1333.     Stolon  creeping, 
covered  with  branching,  hyaline  filaments,  which  adhere  to  the 
substratum.     Frond  ascending,  a  few  cm.  high,  then  recurved 
and  creeping,  irregularly  branched  and  surrounded  by  whorled 
and  imbricated  ramuli,  usually  4  in  a  whorl,  but  varying  from 
2-6  ;  ramuli  cylindrical  at  the  base,  repeatedly  dichotomous,  tips 
forked  or  mucronate.     L,itoral  to  50  m.  depth.     W.  I. 

Canaries,  Mediterranean,  Red  Sea,  Pacific. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  413 

Forma  DISTICHA  Weber,  1898,  p.  270.  Ramuli  patent,  not 
closely  set,  in  distichous,  opposite  series  on  the  rachis.  St. 
Croix . 

Forma  TOMENTELLA  (Harv.)  Weber,  1898,  p.  270;  Vickers, 
1908,  p.  26,  PL  XXXIX.  Frond  more  prostrate  than  in  the 
type,  surrounded  by  very  densely  set,  spreading  ramuli ;  ramuli 
in  the  prostrate  part  of  the  frond  often  prolonged  into  extended 
filaments.  Barbados.  Pacific. 

5.  C.  PROI.IFERA  (Forsk.)  Lamouroux,    18093,  p.  30;  Har- 
vey,   1858,  p.    16,  PI.  XXXVIII. B;  Weber,    1898,  p.   278,  PI. 
XXII,  fig.  i  ;   P.  B.-A.,  No.  269.     Stolon  usually  stout,  naked, 
frond  plane,  linear,  obtuse,  up  to  30  cm.  long  by  3  cm.  wide, 
rarely    divided,    margin    entire,    sometimes    slightly   undulate; 
similar  fronds  often  arising  proliferously  from  any  point  on  the 
original  frond  ;  color  blackish  or  olive  green.     Literal  to  40  in. 
depth.    Fig.  160.    N.  C.  to  Fla.;  W.  I.,  Yucatan.    Mediterranean. 

Forma  OBOVATA  J.  G.  Agardh,  1872,  p.  n  ;  Borgesen,  1907, 
P-  359)  fig-  4-  Frond  shorter  and  broader,  obovate-oblong ; 
same  localities  as  the  type. 

Forma  ZOSTERIFOLIA  Borgesen,  1907,  p.  359,  fig.  6.  Fronds 
narrow-lanceolate,  interrupted  and  abundantly  proliferous.  In 
shallow  water.  St.  Croix. 

Easily  distinguished  from  all  our  other  species  by  the  flat 
frond,  linear  to  rounded  ;  growing  in  sandy  places  at  low  water 
mark  and  in  deeper  water. 

6.  C.  CRASSIFOLIA  (Ag.)  J.  G.  Agardh,  1872,  p.  13  ;  C.pin- 
nata  Weber,  '1898,  p.  289,   PI.  XXIV,  figs.  1-4.     Stolon  creep- 
ing, naked  ;  frond  borne  on  a  cylindrical  or  flattened  pedicel, 
plane,   linear-lanceolate,  pinnate,  up  to  10  cm.  high  ;  pinnules 
opposite,  plane,  at  the  base  as  wide  or  almost  as  wide  as  at  the 
middle,  erect  or  patent,  tip  rounded  or  mucronate.     Literal  to 
30  m.  depth. 

Forma  TYPICA  (Weber)  Borgesen,  1907,  p.  363.  Pinnules 
erect,  sublinear,  not  contracted  at  the'  base,  often  acuminate. 
Fla.  from  Palm  Beach  south  ;  W.  I.  Tropical  seas  generally . 

Forma  MEXICANA  (Sond.)  J.  G.  Agardh,  1872,  p.  13,  (as 
variety);  Vickers,  1908,  p.  26,  PI.  XL;  P.  B.-A.,  No.  80;  C. 
mexicana  Harvey,  1858,  p.  16,  PI.  XXXVII. A.  Pinnules 
erect,  slightly  contracted  at  the  base,  often  enlarged  at  the  sum- 
mit, ending  sharply  in  a  mucro  ;  sinus  between  the  pinnules 
rounded.  Same  distribution  as  the  type. 

Forma  laxior  (Weber)  nov.  comb.;  C.  pinnata  forma  laxior 
Weber,  1898,  p.  291  ;  C.  crassifolia  var.  mexicana  Alg.  Am.- 


414          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

Bor.,  No.  170.  Pinnules  linear,  subpatent,  mucronate,  distinct  ; 
sinus  not  rounded  ;  innovations  of  frond  frequent,  borne  on  long 
pedicels.  Bermuda.  Indian  Ocean. 

The  forms  above  described  are  connected  by  intermediate 
stages.  The  only  species  likely  to  be  mistaken  for  C.  crass/folia 
is  C.  taxifolia,  which  has  narrower,  sickle-shaped,  always  opposite 
pinnae.  C.  crassifolia  forma  pectinata,  (Kiitz.)  nov.  comb.;  C. 
pinnata  forma  pectinata  Weber,  1898,  p.  291,  with  narrow  frond 
and  short,  patent  pinnules,  has  been  found  at  Guyana,  and  is  to 
be  looked  for  in  the  more  southern  West  India  Islands. 

7.  C.    TAXIFOLIA    (Vahl)    Agardh,    1822.   p.    435;    Weber, 
1898,  p.  292;  Vickers,    1908,  p.   26,   PI.   XIJ  ;  P.   B.-A.,   No. 
768;   C.  asplenioides  Greville,    1853,  p.  2,   PI.  I,  fig.  i.     Stolon 
creeping,     naked  ;     frond    plane,     lanceolate-linear,    simple   or 
branched,  pinnate,   up  to  30  cm.  long;  pinnules  sickle-shaped, 
always  opposite,  erect,  distinctly  contracted  at  the  base,   long- 
attenuate  at  the  tip,  ending  in  a  short  mucro  ;  rachis  slender. 
W.  I.     lyitoral  to  30  m.  depth. 

In  some  respects  intermediate  between  C.  crassifolia  and  C. 
sertularioides  ;  distinguished  from  both  by  the  opposite,  sickle- 
shaped,  narrow  pinnules,  with  contracted  base. 

8.  C.  ASHMEADI    Harvey,    1858,  p.    18,   PL  XXXVIII.  A  ; 
Weber,    1898,  p.   293;  Alg.  Am.  -Bor.,   No.  36.     Stolon  stout, 
creeping,  naked  ;   frond  simple  or  branched,  up  to  25  cm.  high, 
base  usually  naked,  above  bearing  long,  linear,  distichous,  usu- 
ally opposite  but  sometimes  alternate  pinnules  ;  pinnules  cylin- 
drical   or    compressed,    2-3    cm.    long,    slightly    increasing   in 
diameter  from  the  base  to  the  obtuse  summit.     Fla.  from  Jupi- 
ter Inlet  to  Key  West  ;   Bermuda,  St.  Thomas;  20-30  m.  depth. 

Apparently  a  rare  plant,  and  probably  only  from  deeper 
water  than  most  species  of  the  genus. 


9.  C.  SERTULARIOIDES  (Gmel.)  Howe,  igosa,  p.  576;  Vick- 
ers, 1908,  p.  26,  PI.  Xlyll  ;  C.plumaris  Harvey,  1858,  p.  17, 
PI.  XXXVIII.  C;  Weber,  1898,  p.  294,  PI.  XXIV,  figs.  5  and 
6;  Alg.  Am.  -Bor.,  No.  .169;  P.  B.-A.,  Nos.  27,  766.  Stolon 
creeping,  naked*;  frond  simple  or  branched,  plane,  linear,  pin- 
nate, up  to  25  cm.  high  ;  pinnules  opposite  or  subopposite, 
cylindrical  or  compressed,  patent,  base  slightly  larger  than  the 
curved  and  mucronate  summit  ;  rachis  narrow,  interval  between 
pinnules  as  wide  as  the  pinnule.  lyitoral  to  4  m.  depth.  Fla., 
W.  I.  All  tropical  seas  . 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  415 

The  appearance  of  the  plant  is  perfectly  described  by  the 
specific  name  p/itmaris,  which  now,  unfortunately,  must  be 
given  up  ;  only  quite  aberrant  forms  are  liable  to  be  mistaken 
for  anything  else.  The  four  forms  described  below  occur 
within  our  limits  ;  forma  brcvipcs  and  forma  longipes  are  found 
everywhere  with  the  type,  of  which  they  are  merely  extreme 
forms  ;  forma  longiseta  is  from  Jamaica,  forma  Farlowii  from 
Florida. 

Forma  BREVIPES  (J.  Ag.)  Svedelius,  1906,  p.  114,  fig.  7  ;  C. 
pi  it ///art's  forma  brevipcs  Weber,  1898,  p.  294.  Frond  simple, 
the  pinnules  extending  to  the  base  of  the  rachis. 

Forma  longipes  (Ag.)  nov.  comb.  ;  C.  plnmaris  forma  longipes 
Weber,  1898,  p.  295.  Frond  branching,  pedicelled,  without 
pinnules  for  a  long  distance  at  the  base. 

Forma  LONGISETA  (J.  Ag.)  Svedelius,  1906,  p.  114,  fig.  10 ; 
C.  plum aris  forma  longiseta  Weber  1898,  p.  295.  Pinnules  fine, 
long  (2  cm.)  and  close  together. 

Forma  FARLOWII  (Weber)  Borgesen,  1907,  p.  365  ;  C.  plu- 
maris  forma  Farlowii  Weber,  1898,  p.  295.  Pinnules  opposite, 
alternate,  in  pairs,  or  even  in  several  rows. 

TO.  C.  LYCOPODIUM  Harvey,  1858,  p.  19,  PI.  XXXVII. B  ; 
Weber,  1898,  p.  304;  C.  lanuginosa  Alg.  Am-Bor. ,  No.  37. 
Stolon  and  base  of  fronds  covered  with  woolly  hairs ;  frond 
up  to  10  cm.  high  ;  from  the  point  where  the  hairs  cease,  cov- 
ered with  simple,  bristle-like,  imbricate,  serrate  ramuli,  ending 
sharply  in  a  mucro ;  branches  of  the  middle  of  the  frond  longer 
than  those  nearer  the  base  or  the  summit.  Fla.,  W.  I. 

Var.  DELICATULA  (Grun.)  Weber,  1898,  p.  305,  PI.  XXV, 
fig.  2.  Plant  very  slender,  not  over  3  cm.  high  ;  ramuli  fili- 
form, erect,  slightly  acuminate.  Fla.  Pacific,  Australia. 

This  seems  to  be  merely  a  dwarf  form,  but  it  is  of  interest  as 
occurring  both  at  Florida  and  on  the  opposite  side  of  the, globe, 
while  the  type  occurs  only  in  Florida. 

ii.  C.  FREYCINETII  Agardh,  1822,  p.  446;  Weber,  1898, 
p.  310,  PI.  XXV,  figs.  4-1 1  ;  XXVI,  figs.  1-6;  Phyk.  Univ., 
No.  326.  Stolon  usually  stout,  creeping,  naked  ;  frond  cylin- 
drical or  compressed  at  the  base,  then  plane,  linear,  foliaceous, 
often  spirally  twisted,  often  alternately  constricted  and  widened, 
branching  always  dichotomous,  margin  dentate,  serrate,  or 
entire. 

As  indicated  by  this  description,  this  species  varies  greatly, 


4i6  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

including  forms  which,  before  the  intermediate  gradations  had 
been  seen,  passed  without  question  as  distinct  species.  Four 
varieties  are  recognized  by  Mme.  Weber,  of  which  we  have 
three,  all  occurring  at  Guadeloupe. 

Var.  TYPICA  Weber,  1898,  p.  312.  Frond  usually  spirally 
twisted,  frequently  narrowed  and  dilated,  margin  dentate,  teeth 
as  long  as  or  longer  than  their  width. 

Forma  ANGUSTA  Weber,  1898,  p.  313.  Frond  narrow,  the 
interior  margin  of  the  spiral  entire,  the  outer  dentate  ;  constric- 
tions few. 

Forma  LATA  Weber,  1898,  p.  313.  Frond  broader;  both 
margins  dentate  ;  constrictions  frequent. 

Var.  DE  BORYANA  (Ag.)  Weber,  1898,  p.  315.  Frond  sim- 
ple, cylindrical  or  compressed,  for  a  long  distance  before  fork- 
ing;  then  plane,  little  or  not  at  all  twisted,  dentate;  teeth 
distant. 

Forma  OCCIDENTALIS  Weber,  1898,  p.  315.  Frond  not 
twisted,  teeth  small,  usually  wider  than  long.  The  typical 
variety  de  Boryana  occurs  in  the  Red  Sea  ;  the  forma  occiden- 
talis  at  Guadeloupe  only. 

Var.  PECTINATA  (Maze  and  Schramm)  Weber,  1898,  p.  316; 
Vickers,  1908,  p.  28,  PI.  XLJVc.  Frond  very  rarely  twisted ; 
constrictions  few  or  many  ;  proliferations  often  frequent ;  margin 
of  foliaceous  part  dentate  or  pectinate ;  constrictions  naked. 
W.  I. 

12.  C.  CUPRESSOIDES  (Vahl)  Agardh,  1822,  p.  441  ;  Weber, 
1898,  p.  323,  Pis.  XVII  and  XVIII  ;  Harvey,  1858,  p.  21,  PI. 
XXXIX. B;  Alg.  Am.-Bor.,  No.  96  ;  P.  B.-A.,  Nos.  79,  575, 
765.  Stolon  usually  stout,  naked  ;  branches  of  frond  dichoto- 
mous,  fastigiate  or  irregular,  surrounded  by  ramuli ;  ramuli 
distichous,  tristichous,  or  multiseriate,  "  sub-navicular "  in 
form,  with  broad  base  at  the  central  axis  and  rounded  dorsally  ; 
other  ramuli  ovoid,  conical,  compressed,  or  even  cylindrical ; 
always  mucronate.  Literal  to  30  m.  depth.  Fla.,  W.  I. 

An  extremely  variable  species,  including  many  species  of 
earlier  authors,  species  apparently  distinct  in  themselves,  but 
now  found  to  be  connected  by  every  gradation.  The  varieties 
given  below  indicate  mostly  the  typical  forms  of  these  supposed 
species,  and  must  be  considered  merely  as  showing  the  range  of 
variation.  The  best  test  for  the  species  as  a  whole  is  the  pres- 
ence of  the  "sub-navicular"  or  "  rostriform  "  ramuli.  Kven 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  417 

when  the  ramuli  as  a  whole  are  of  one  or  more  of  the  numerous 
forms  found  in  this  species,  there  will  always  be  a  few  of  the 
characteristic  shape  near  the  base  of  the  frond. 

Var.  TYPICA  Weber,  1898,  p.  326  ;  Vickers,  1908,  p.  27,  Pis. 
XLIV,  XLIVb.  Frond  and  its  branches  with  naked  base, 
otherwise  surrounded  by  sub-navicular  ramuli,  in  3  ranks 
(rarely  in  2,  4  or  5  ranks)  ;  length  of  ramuli  up  to  twice  the 
diameter  of  the  axis.  W.  I.  India. 

Var.  TURNERI  Weber,  1898,  p.  330.  Frond  slender,  ramuli 
in  3  or  4  ranks,  sub-navicular  or  conical,  small,  length  hardly 
equalling  the  diameter  of  the  axis,  appressed,  or  nearly  so. 
Fla.,  W.  I. 

Var.  SERRATA  (Kiitz.)  Weber,  1898,  p.  331.  Frond  slender, 
with  elongate  branches,  dichotomous,  alternate,  or  fascicled  ; 
in  places  naked,  but  usually  near  the  summit  with  ramuli  in  2 
or  3  ranks.  Ramuli  small,  erect  or  horizontal,  sub-navicular, 
opposite  or  alternate  ;  length  hardly  equalling  the  diameter  of 
the  axis.  Guadeloupe.  Venezuela. 

Apparently  a  reduced  and  depauperate  form  of  vars.  typica 
and  Turneri,  due  to  growth  under  unfavorable  conditions. 

Var.  MAMMILLOSA  (Mont.)  Weber,  1898,  p.  332  ;  Alg.  Am.- 
Bor.,  No.  96.  Primary  axis  of  the  frond  naked  or  covered  with 
mammilliform  or  obtuse  ramuli ;  branches  issuing  at  acute 
angles,  covered  from  the  base  with  obovoid  or  sub-navicular, 
mucronate,  erecto-patent  ramuli,  in  5  or  more  ranks  ;  length  of 
ramuli  hardly  equalling  the  diameter  of  the  axis. 

Forma  TYPICA  Weber,  1898,  p.  332.  Base  of  central  axis 
surrounded  by  mammilliform  ramuli.  Fla.,  W.  I. 

Australia,   So.  Pacific. 

Forma  NUDA  Weber,  1898,  p.  332.  Base  of  central  axis  not 
surrounded  by  mammilliform  ramuli.  Fla.,  W.  I. 

Var.  ERICIFOLIA  (Turner)  Weber,  1898,  p.  335.  Frond  sur- 
rounded by  multiseriate  cylindrical  ramuli,  appressed  to  the 
axis  ;  length  about  the  diameter  of  the  axis.  W.  I. 

Var.  LYCOPODIUM  (Ag.)  Weber,  1898,  p.  335.  Frond  tall, 
generally  little  branched,  ranruli  erecto-patent  in  two  ranks,  or 
erect  in  several  ranks,  sub-navicular  at  the  base  of  the  frond, 
cylindrical  above,  2-6  times  as  long  as  the  diameter  of  the  usu- 
ally slender  axis. 

Forma  ALTERNIFOLIA  Weber,  1898,  p.  336-*     Frond  dichoto- 

*Bbrgesen,  1907,  p.  368,  fig.  17,  proposes  the  name  forma  plumarioides 
for  forma  alternifolia  and  forma  elegans  of  var.  Lycopodium,  with  de- 
scription as  follows  :  Branches  long,  rather  weak  ;  ratuuli  in  2  or  3  rows, 


418          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

mous ;  a  great  part  of  the  ramuli  sub-navicular,  the  rest  cylin- 
drical ;  the  former  generally  in  3  ranks,  the  latter  distichous 
and  opposite,  or  multiseriate ;  length  up  to  twice  the  diameter 
of  the  axis.  Axis  without  naked  base  or  with  a  very  short  one. 

Forma  ELEGANS  (Crouan)  Weber,  1898,  p.  336;  Vickers, 
1908,  p.  27,  PI.  XLIIIb.  Frond  dichotomoiis,  ramuli  nearly 
all  cylindrical,  only  a  few  at  the  base  sub-navicular ;  length  up 
to  6  times,  usually  3  or  4  times  the  diameter  of  the  axis ; 
distichous  and  opposite. 

Forma  INTERMEDIA  Weber,  1898,  p.  337.  Frond  very  lux- 
uriant, up  to  30  cm.  high  ;  ramuli  all,  except  those  of  the  base, 
cylindrical,  in  two  or  more  series;  base  naked  fora  longer  or 
shorter  distance. 

Forma  TYPICA  Weber,  1898,  p.  337  ;  Vickers,  1908,  p.  27, 
PL  XLJII.  Frond  lower  than  in  the  preceding  forms,  simple 
or  branched ;  ramuli  always  multiseriate,  cylindrical  except 
those  at  the  base,  length  up  to  4  times  the  diameter  of  the  axis. 

All  four  of  these  forms  at  Guadeloupe,  among  the  Maze  and 
Schramm  exsiccatae,  under  various  names  ;  some  also  at  Barba- 
dos ;  forma  alternifolia  at  Fla. 

Var.  DISTICHA  Weber,  1898,  p.  338.  Frond  often  much 
branched,  base  naked ;  ramuli  all  except  the  lowest  cylindrical 
and  opposite  in  two  ranks,  except  occasionally  multiseriate  near 
the  summit  ;  ramuli  erecto-patent,  up  to  twice  the  diameter  of 
the  axis.  Fla.,  W.  I. 

13.  C.  PASPALOIDES  (Bory)  Harvey,  1858,  p.  21  ;  Weber, 
1898,  p.  350,  PI.  XXX  ;  Alg.  Am.-Bor.,  No.  38.  Stolon  ro- 
bust, up  to  4  mm.  diam.;  frond  of  a  naked  stipe  (or  pedicel), 
simple  or  dichotomous,  bearing  at  its  summit  simple,  dichoto- 
mous,  or  palmate  branches,  covered  with  ramuli ;  ramuli  in  3 
or  4  alternating  ranks,  subverticillate  or  inclined  to  right  and 
left,  with  bases  in  contact,  imbricate  or  distinct,  pinnate  ;  pin- 
nules inclined  to  one  side,  bases  adjacent  or  opposite,  simple, 
forked,  or  again  pinnate,  pinnules  almost  always  mucronate. 

A  species  of  very  characteristic  habit,  better  recognized  from 
specimen  or  plate  than  from  description  ;  it  is  limited  to  Florida, 
the  West  Indies,  Gulf  of  Mexico  and  Carribbean  Sea ;  includ- 
ing three  varieties  and  a  number  of  forms,  not  clear  from  each 
other,  but  not  likely  to  be  mistaken  for  any  other  species  when 
one  has  a  clear  idea  of  the  type. 

curved  upwards,  cylindrical,  3-4  times  as  long  as  the  width  of  the  rachis. 
He  considers  it  a  form  of  shallow  lagoons. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA          419 

Var.  TYPICA  Weber,  1898,  p.  352.  Pedicel  of  varying  height, 
branches  cylindrical  or  flattened,  ramuli  pinnate,  subverticillate, 
alternate,  and  imbricate,  sometimes  leaving  a  naked  strip  along 
the  back  of  the  branch. 

Forma  PASPALOIDES  Weber,  1898,  p.  352.  Branches  sub- 
cylindrical  ;  ramuli  pinnate  ;  pinnules  with  bases  adjacent, 
forked  or  with  a  single  row  of  secondary  pinnules. 

Forma  PHLEOIDES  (Bory)  Weber,  1898,  p.  353.  Branches 
subcylindrical,  ramuli  pinnate,  pinnules  with  adjacent  bases, 
with  twyo  rows  of  secondary  pinnules. 

Forma  COMPRESSA  Weber,  1898,  p.  353.  Pedicel  very  short, 
1-2  cm.  long;  branches  2-3  cm.  long,  cylindrical,  digitate  at 
the  summit  of  the  pedicel,  surrounded  by  very  dense,  imbricate 
ramuli  in  many  indistinct  ranks;  ramuli  small,  plane,  with 
simple  or  forking,  opposite  or  subopposite,  pinnately  distichous, 
patent  pinnules. 

Forma  FLABELLATA  Weber,  1898,  p.  353.  Pedicel  up  to  n 
cm.  high  ;  branches  simple  or  branched,  flabellately  arranged 
at  the  summit  of  the  pedicel,  flattened,  ramuli  distinctly  in- 
clined to  right  and  left,  with  bases  adjacent,  dense,  but  not  as 
much  so  as  in  the  preceding  forms  ;  pinnules  inclined  to  one 
side,  biseriate,  simple  or  forked. 

Var.  WURDEMANNI  Weber,  1898,  p.  353.  Pedicel  about  8 
cm.  high  ;  branches  10  cm.  or  more,  with  biseriate,  subopposite 
or  scattered  ramuli,  bearing  biseriate,  simple,  unilateral  pin- 
nules. 

Forma  PHYLLOPHLASTON  (Murray)  Weber,  1898,  p.  353  ;  C. 
phyllophlaston  Murray,  1891,  p.  207,  PI.  LIU,  figs.  3-6.  Pin- 
nules uniseriate. 

Var  LAXA  Weber,  1898,  p.  353.  Pedicel  up  to  18  cm.  high; 
branches  up  to  28  cm.;  arising  fasciculately  at  the  summit  of 
the  pedicel,  surrounded  by  very  small,  distant,  subverticillate 
ramuli  ;  pinnules  small,  simple,  unilateral. 

Var.  Wurdemanni  forma  phyllophlaston  has  so  far  been  found 
only  in  Yucatan  ;  the  other  varieties  and  forms  at  Florida  and 
the  West  Indies. 

14.  C.  RACEMOSA  (Fb'rsk.)  J.  G.  Agardh,  1872,  p.  35  ; 
Weber,  1898,  p.  357,  PI.  XXXI,  figs.  5-8;  XXXII,  figs.  1-7  ; 
XXXIII  ;  P.  B.-A.,  Nos.  767,  870;  C.  davifera  Harvey,  1858, 
p.  19;  Alg.  Am.-Bor.,  No.  39;  P.  B.-A.,  No.  270.  Fronds 
robust  or  delicate,  simple  or  branched,  ramuli  distichous,  alter- 
nate, opposite,  multiseriate,  or  imbricate.  Ramuli  with 
rounded  or  plano-convex  summit,  enlarging  insensibly  from  the 


420  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

base  to  the  summit,  or,  where  there  is  a  distinct  pedicel,  the 
passage  from  the  pedicel  to  the  summit  is  not  sudden. 

One  of  the  most  variable  of  Caulerpas,  covering  many  former 
species,  now  arranged  under  varieties  and  forms  that  give  no 
sharp  division  lines  ;  occurring  in  one  form  or  another  all  over 
the  world,  mostly  in  shallow  water.  Of  the  8  varieties  given 
by  Mme.  Weber,  5  occur  with  us,  also  another  variety  of  Borge- 
sen  ;  the  following  key  may  be  some  guide  to  them. 

i.  Ramuli  usually  pyriform-obovoid,  with  globular  or  subglobular  sum- 
mit, occasionally  laterally  flattened  ;  pedicel  not  over  half  the 
total  length  of  the  ramulus.  2. 

i.  Ramuli  claviform  with  rounded  or  trumpet-shaped  summit ;  some- 
times also  cylindrical  ramuli  present ;  pedicel  often  more  than 
half  the  total  length  of  the  ramulus.  3. 

2.     Fronds  with  distant,  alternate  or  distichous  and  subopposite  ram- 
uli, usually  pyriform  with  globular  summit.        Var.  clavifera. 
2.     Fronds  with  multiseriate,  imbricate,  obovoid  or  obovoid-compressed 

ramuli.  Var.  uvifera. 

3.     Slender  and  delicate  plants.  Var.  gracilis. 

3.     Stout.  4. 

4.     Ramuli  multiseriate,  densely  imbricate.  5. 

4.     Ramuli  few  or  wanting.  Var.  Lamouron.rii. 

5.     Ramuli  rather  uniformly  increasing  in  size  to  summit. 

Var.  laetevirens. 
5.     Ramuli  suddenly  expanded  at  summit.  Var.  occidentalis. 

Var.  CLAVIFERA  (Turn.)  Weber,  1898,  p.  361  ;  Vickers, 
1908,  p.  28,  PI.  XLV.  Slender,  i-n  cm.  high,  ramuli  gener- 
ally distant,  usually  pyriform  with  globular  summit,  1-2.5  mm. 
diam.,  and  short  pedicel.  Fla.,  W.  I.  All  tropical  seas, 

Forma  MACROPHYSA  (Ku'tz.)  Weber,  1898,  p.  361  ;  P.  B.-A., 
No.  870.  Ramuli  with  globular  summit  4-5  mm.  diam.  Jam- 
aica, St.  Croix. 

Var.  UVIFERA  (Turn.)  J.  G.  Agardh,  1872,  p.  35.  Frond 
cylindrical,  simple  or  branched,  with  very  dense,  multiseriate 
ramuli  ;  ramuli  usually  obovoid,  sometimes  globular.  Red  Sea. 
Forma  CONDENSATA  (Kiitz.)  Weber,  1898,  p.  363.  Ramuli 
very  dense  at  the  base  of  the  frond,  more  open  near  the  top. 
W.  I.  (forma  condensata  only). 

Var.  OCCIDENTALIS  (J.  Ag.)  Borgesen,  1907,  p.  379,  figs.  28 
and  29.     Ramuli  subcylindrical  and  rather  loosely  set  at  the 
base  of  the  rachis,  more  clavate  and  closer  above,  densely  im- 
bricate at  the  summit ;  top  of.  ramuli  always  convex.     W.  I. 
Var.    LAETEVIRENS  (Mont.)  Weber,    1898,  p.   366.     Fronds 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  421 

robust,  up  to  12  cm.  high,  ramuli  imbricate,  very  dense.  Ram-' 
uli  clavate  with  rounded  or  hemispherical  summit,  or  sometimes 
cylindrical. 

Forma  TYPICA  Weber,  1898,  p.  366.  Ramuli  with  swollen 
summit,  turned  more  or  less  to  one  side.  Fla.,  W.  I. 

-•litstralian,  Indian  and  Pacific  Oceans, 

Var.  LAMOUROUXII  (Turn.)  Weber,  1898,  p.  368.  Frond  tall, 
up  to  16  cm.,  with  distichous,  alternate,  subopposite,  or  scat- 
tered, pyriform  or  clavate  ramuli.  Guadeloupe. 

Red  Sea,  Pacific. 

Var.  GRACIUS  (Zan.)  Weber,  1898,  p.  370.  Frond  slender 
and  elongate,  often  creeping,  with  rare  cylindrical  ramuli,  or 
with  a  considerable  number  of  small  clavate  ramuli.  Sand 
Key,  Fla. 

Possibly  only  a  depauperate  form  of  C.  racemosa. 

15.  C.  PET/TATA  (Turn.)  Lamouroux,    iSoga,  PI.  Ill,  fig.  2  ; 
Weber,  1898,  p.  373,  PI.  XXXI,  figs.  9-11  ;  XXXII,  fig.  8  ;   C. 
inacrodisca    Phyk.     Univ.,    No.    374.     Stolon    naked,  creeping, 
branched,  robust  or  delicate  ;  frond  delicate,  simple  or  branched, 
with  simple,  peltate,  scattered  ramuli,  with  a  diameter  of  3-8 
mm.,  usually  3-5  mm. 

Var.  TYPICA  forma  IMBRICATA  (Kjellman)  Weber,  1898,  p. 
375.  Central  axis  of  the  frond  surrounded  by  very  dense 
ramuli.  W.  I.  (T5-pe  and  forma  imbricata.} 

1 6.  C.  AMBIGUA  Okamura,  1897,  p.  4,  PL  I  ;  Weber,  1898, 
p.  388;  Vickers,    1908,   p.   25,   PI. XXXVII ;  Okamura,  Algae 
Japonicae  Exsicc.,  No.  95.     Stolon  wanting  ;  frond  attached  by 
rhizoids,  minute,  filiform,  solitary,  erect,  divergently  branched, 
with  not  very  closely  set,  subdistichous  or  multiseriate  ramuli 
of   diameter  about    equal   to   that   of   the   axis,   cylindrical  or 
slightly  clavate,  slightly  or  not  at  all  contracted  at  the  base. 
Barbados.  Japan. 

The  smallest  species  of  the  genus  and  remarkable  for  the 
total  absence  of  the  stolon.  It  is  hardly  likely  that  it  occurs 
only  at  the  two  widely  separated  stations  now  known,  but  it  has 
probably  been  overlooked  elsewhere  on  account  of  its  small  size. 

Family  6.     VAUCHERIACEAE. 

Fronds  filamentous,  cylindrical  or  with  frequent  constrictions, 
with  lateral  or  dichotomous  branching ;  chromatophores  small 
disks,  without  pyrenoid  ;  asexual  reproduction  by  large,  multi- 
ciliate  zoospores  ;  also  by  aplanospores  and  akinetes  ;  sexual 
reproduction  by  oogonia  and  antheridia. 


422          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

KEY  TO  THE  GENERA  OF  VAUCHERIACEAE. 

i.     Filaments  cylindrical.  i.     VAUCHERIA. 

i.     Filaments  with  frequent  constrictions.  2.     DICHOTOMOSIPHON. 

i.     VAUCHERIA  De  Candolle,  1805,  p.  61. 

Fronds  filamentous,  inarticulate,  branches  arising  laterally 
but  often  assuming  a  dichotomous  appearance  ;  forming  more  or 
less  dense  tufted  or  felty  masses,  usually  attached  by  colorless 
rhizoids ;  numerous  small  chromatophores  without  pyrenoids, 
and  with  very  minute  nuclei.  Asexual  reproduction  by  very 
large  zoospores,  covered  with  cilia,  with  a  small  nucleus  corre- 
sponding to  each  pair  of  cilia  ;  produced  in  the  somewhat  cla- 
vate  ends  of  branches,  partitioned  off  from  the  rest  of  the  frond ; 
germinating  immediately  ;  by  aplanospores  produced  usually  at 
the  ends  of  short  branches,  arising  similarly  to  zoospores,  but 
without  cilia,  germinating  only  after  a  longer  or  shorter  period 
of  rest ;  also  in  some  species  by  akinetes,  the  filament  break- 
ing up  into  short  portions,  each  with  a  thick  wall.  Sexual  re- 
production by  oogonia  and  antheridia,  of  quite  variable  shape  and 
position  ;  usually  on  the  same  filament,  but  in  some  species  on 
distinct  individuals  ;  oogonium  sessile  or  pedicellate,  partitioned 
off  from  the  frond  and  producing  a  large,  globose,  or  subglobose 
uninucleate  oospore  ;  antheridium  similarly  located  and  parti- 
tioned off  from  the  frond,  producing  many  biciliate  spermato- 
zoids,  with  cilia  pointing  in  opposite  directions ;  when  the 
oospore  is  formed,  the  end  of  the  oogonium  dissolves,  and  the 
spermatozoids  enter,  fertilizing  the  oospore,  which  germinates 
after  a  resting  period. 

A  widely  distributed  genus  of  unattractive  appearing  plants, 
but  interesting  by  their  elaborate  and  varied  fructification. 
Mostly  fresh  water  species,  they  often  extend  into  brackish 
water,  and  some  are  strictly  marine.  Sterile  plants  are  quite 
indeterminable,  and  fruit  is  not  always  easy  to  find  ;  and  in 
dried  material  or  herbarium  specimens  the  fruit  is  not  in  as 
good  condition  for  study  as  in  most  other  algae. 

KEY  TO  THE  SPECIES  OF  VAUCHERIA. 

i.     Antheridia  not  separated  from  the  frond  by  an  empty  cell.  2. 
i.     Autheridia  separated  from  the  frond  by  an  empty  cell. 

PH,OBOI,OIDEAE.     14. 

2.     Antheridia  little  or  not  at  all  curved.     TUBULIGERAE.  3. 

2.     Antheridia  hooked  or  circinate.     CORNICU^ATAE.  7. 

3.     Oogonia  spherical  or  nearly  so.  4. 

3.     Oogouia  more  or  less  ovoid  or  oblique.  5. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  423 

4.     Dioecious ;  oogonia  sessile.  5.     V.  dichotoma. 

4.     Monoecious;  oogonia  somewhat  stipitate.  2.     V.  Tluirefii. 

5.     Oogonia  facing  in  opposite  directions.  4.      V.  aversa. 

5.     Oogonia  single,  or  several  facing  one  way.  6. 

6.     Oogonium  usually  single.  i.      V.  Dillwynii. 

6.     Oogonia  in  series  of  2-6.  3.     V.  ornithocephala. 

7.     Oogonia  sessile  on  the  main  filament  or  very  shortly  stipitate. 

SESSILES.    8. 

7.     Oogonium  on  a  branch  or  distinct  pedicel,  antheridium  terminal. 

RACEMOSAE.    10. 

8.     Oogonia  straight.  8.     V.  orthocarpa. 

8.     Oogonia  oblique.  9. 

9.     Filaments  33-50  ,u  diam.  •  6.     V.  repens. 

9.     Filaments  50-85  M  diam.  7.     V.  sessilis. 

10.     Oogonium  sessile  on  the  branch,  or  nearly  so. 

10.  V.  terrestris. 
10.     Oogouia  stipitate.  n. 

ii.     Oogonium  usually  solitary.  9.      V.  hamata. 

ii.     Oogonia  usually  2-6.  12. 

12.     Pedicels  of  oogonia  and  antheridia  arising  from  same  point  on 

main  filament.  13.      V.  Gardneri. 

12.     Pedicels  of  oogonia  and   antheridia  arising  near  the  end  of  a 

branch.  13. 

13.     Branch  short ;  antheridium  usually  surpassing  oogonia. 

11.  V.  getninata. 
13.     Branch  long;  antheridium  not  surpassing  oogonia. 

12.     V.  longipes. 

14.     Oogouium  separated  from  filament  by  an  empty  cell. 

1 8.      V.  litorea. 

14.     Oogonium  not  separated  from  filament  by  an  empty  cell.         15. 
15.     Oogoninm  with  many  fecundation  tubes.  17.     V.  coronata. 

15.     Oogonium  with  only  one  fecundation  tube.  16. 

16.     Oospore  spherical.  17. 

16.     Oospore  lentiform.  14.     V.  piloboloides. 

17.     Antheridium  truncate.  16.     V.  intermedia. 

17.     Antheridium  acute.  15-     V.  sphaerospora. 

i.  V.DILLWYNII  (Web.  and  Mohr)  Agardh,  1810,  p.  21; 
Wittr.  and  Nordst.,  Alg.  Exsicc.,  No.  1583;  V.  p&chyderma 
Walz,  1866,  p.  146,  PI.  XII,  figs.  1-6.  Terrestrial;  filaments 
60-100  p.  diam.;  oogonia  globose  or  ellipsoid,  sometimes  sub- 
reniform,  sessile,  rostrate,  generally  solitary,  occasionally  two 
together,  about  150  ^  diam.;  membrane  with  fine  dots;  ripe 
oospore  with  brown  spots,  with  thick  wall,  manifestly  lamellate, 
sometimes  up  to  7  layers  ;  antheridia  saccate,  formed  at  the  ends 
of  short,  hooked  lateral  branches,  20  p.  diam.,  near  the  single 
oogonium,  or  between  two  approximate  oogonia.  Me.,  N.  J. 

Europe. 


424          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

2.  V.  THURETII  Woronin,   1869,  p.  157,  PL  II,  figs.  30-32; 
Farlow,  1881,  p.  104;   P.  B.-A.,   No.  1029.     Marine;  filaments 
varying  considerably,  but  reaching  8o,udiatn.;  antheridia  ses- 
sile, ovoid,  50-70  p.  wide,    100-150  ^  long;    oogonia    sessile  or 
oftener  on   short    lateral    branches,    obovoid   or   pyriform,    in- 
clined,  200  fj.  wide,  250-300  /JL  long;  oospores  150-180  //.  diam.; 
aplanospores  ovoid,  80X100-120  /A,  on  short  branches  at  right 
angles  to  the  filaments.     Me.  to  N.  J.  I^urope. 

Forming  dense  dark  green  patches  in  muddy  ditches  by  the 
shore,  probably  extending  farther  south  than  the  N.  J.  station. 
The  filaments  of  the  American  plant  appear  to  be  usually  con- 
siderably smaller  than  those  described  and  figured  by  Woronin 
for  the  European  plant,  sometimes  as  low  as  30  ^,  but  otherwise 
they  agree. 

3.  V.  ORNITHOCEPHALA  Agardh,    1817,   p.  49;    P.   B.-A., 
No.  984;    V.  scricea  Walz,    1866,  p.  150,   PI.  XIII,  figs.  20  and 
21  ;  Wolie,  1887,  p.  150,   PI.   CXXVII,  figs.  12  and   13.     Fila- 
ments 35-45  p-  diam.,  oogonia  2-6-seriate,  unilateral,  obliquely 
ovoid,    100-150  p.  diam.,    i^    diam.   long,   opening   through   a 
broad  beak,  sessile  or  very  short-pedicelled  and  in  form  not  un- 
like a  bird's  head  ;  oospore  nearly  globose,  about  as  wide  as  the 
oogonium,  but  not  filling  it  longitudinally,  reddish  when  ripe, 
with  triple  membrane ;    antheridia  one  or  two  at  one  end  of  a 
series  of  oogonia,  cylindric  to  subclavate,  20-25  /x  diam.,  about 
4   diam.    long,    bent   nearly  horizontally;    zoospores    83-iooX 
90-115  /A,  in  cylindrical  or  very  slightly  clavate  sporangia  ;  the 
cilia  much  more  closely  set  at  the  forward  end.     Occurs  mostly 
in  running  water.     Mass.,  Pa.  Europe. 

The  seriate  oogonia  with  their  birds'  heads  facing  the  anther- 
idium  at  one  end,  make  a  pretty  good  mark  for  distinguishing 
this  from  species  hitherto  reported  in  America,  but  the  same 
characters  are  found  in  the  European  V.  polyspcrma  Hassall, 
which  very  likely  will  sometime  be  found  here.  It  is  more 
slender  throughout,  the  filaments  22-33  /*>  the  oogonia  60-65  M 
diam.,  and  more  nearly  erect ;  zoospores  66-88  /A  diam.;  anther- 
idium  always  single. 

4.  V.  AVERSA  Hassall,    i843b,  p.  429  ;    1845,  p.  54,  PL  VI, 
fig.  5;   Walz,  1866,  p.  151,  PL  XIII,  figs.  25  and  26^;   PL  XIV, 
fig.  27  ;   Wolle,  1887,  p.  149,  PL  CXXVII,  figs.  5-8;   P.  B.-A., 
No.  475.     Filaments  60-100  /*  diam.;  oogonia  obliquely  ovoid, 
sessile   or   shortly  stipitate,    two,  rarely  more    in    a    series,  the 
beaks  usually  in  opposite  directions,  mostly  erect,    125X250/11; 


THE  GRKEN  ALGAE  OF  NORTH  AMERICA  425 

oospore  globose  or  ovoid,  with  triple  membrane,  75-100  p.  diam., 

not  filling  the  oogonium ;    antheridia  cylindric  or  subclavate, 

'30-40  p.  diam.,  erect,  more  or  less  incurved,  on  each  side  of  the 

series  of  oogonia.     In  ponds  and  ditches.     Mass.,  Conn.,  Neb., 

Cal.  Europe. 

The    distinguishing   mark  for   this    species  is  found    in    the 

oogonia  facing  in  opposite  directions. 

5.  V.  DICHOTOMA  (L,.)  Agardh,  1817,  p.  47;  Walz,  1866,  p. 
152,   PI.  XIV,   figs.   28-33  ;  Wolle,  1887,   p.  149,   PI.   CXXVI, 
figs.    1-7;    Wittr.  and  Nordst.,   Alg.   Exsicc.,   Nos.   337,   338. 
Dioecious,  filaments  135-200  p.  diam.,  oogonia  sessile,  300-400  p. 
diam.,   globose  or  ovoid-globose,  distant  or  2-6  approximate; 
ripe  oospore  with  triple  membrane,  brown  spotted  ;  antheridia 
erect,  ovoid,  90-150X150-250^.     In  ponds  and  ditches.     W.  I. 

Europe. 

Recorded  by  Wolle  without  definite  locality.  V.  Pihts  Wolle, 
1887,  p.  153,  PI.  CXXVII,  figs.  1-4,  from  Vt.,  may  be  a  form 
of  this  species. 

6.  V.  REPENS  Hassall,   i843b,  p.  430;   1845,  p.  52,  PI.  VI, 
fig.    7;    Gotz,    1897,    P-    IIO>    fig8-    14-16.     Filaments   33-50  p. 
diam.  ;    oogonia    single,    rarely   two,    sessile,    obliquely    ovoid, 
70-80X55-80  p.,   ending  in   a  short  beak,    usually  horizontal; 
oospore   quite    filling   the   oogonium,  grayish,  coarse  grained, 
with  triple  membrane  and  one  or  more  brown  spots ;  antherid- 
ium  close  to  the  oogonium,  circinate,  on  a  straight  or  curved 
pedicel;  zoospores  80-130X75-120  p.,  formed  in  nearly  cylindri- 
cal sporangia  ;   cilia  uniformly  distributed.     On  moist   ground 
or  submerged.     Cal.  Europe. 

7.  V.  SESSILIS  (Vauch.)  De  Candolle,  1805,  p.  63  ;  Kiitzing, 
1856,  PI.  LIX,  fig.  2  ;   Wolle,  1887,  p.  151,  PI.  CXXVII,  figs. 
9-1 1  ;  Gotz,  1897,  p.  in,  figs.  17-22;  P.  B.-A.,  No.  228.     Fil- 
aments 50-85  p.  diam.;  oogonia  usually  two,  sometimes  single, 
sessile,   ovoid  or  oblong-ovoid,   70-85X75-100  p.,  more  or  less 
oblique,  with  short  beak  ;  antheridium  between  the  oogonia  or 
beside  the  single  oogonium,  on  a  short  pedicel,  straight,  hooked 
or  circinate  ;  ripe  oospore  dark-spotted,  with  triple  membrane, 
filling  the  oogonium  ;  zoosporangia  ovoid-clavate,  terminal  on 
a  branch  which  is  however  sometimes  so  short  that  the  spor- 
angium   appears   sessile;    zoospores    110-145X110-125   p.,  with 
cilia  evenly  distributed.     Me.,  Mass.,  R.  I.,  Conn.,  N.  J.,  Neb., 
Alaska  to  Cal.  Europe. 

A  common  species  in  brooks  and  ditches. 

8.  V.  ORTHOCARPA  Reinsch,  1887,  p.  189,  PI.  VIII ;    V.  da- 


426          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

vata  Gotz,  1897,  p.  114,  figs.  23-28;  an  Ectospcrma  clavata 
Vaucher?  Filaments  77-110  p.  diain.;  oogonia  one  or  two,  ses- 
sile, 55-75X80-110  /A,  narrowly  ovoid,  erect,  with  a  short  and 
broad  vertical  beak;  oospore  of  same  shape,  50-65X65-90  /x 
with  a  red  central  spot  and  triple  membrane  ;  antheridium  soli- 
tary beside  a  single  oogonium  or  between  two  oogonia,  circi- 
nate,  on  a  straight  or  recurved  pedicel  ;  zoospores  I25-I5OX 
135-175  /".,  in  broadly  clavate  sporangia  ;  cilia  uniformly  distrib- 
uted. In  ponds  and  ditches.  Cal.  Europe. 
The  three  species,  V.  repens,  V.  sessilis  and  V.  orthocarpa  are 
certainly  closely  related,  but  Gotz,  who  has  studied  them  more 
than  any  other  observer,  considers  them  distinct.  Beside  the 
differences  in  dimensions  of  filaments  and  dimensions  and  shape 
of  oogonia,  he  notes  physiological  characters,  which  it  is  not 
practicable  to  give  here  in  detail.  As  far  as  Vaucher's  descrip- 
tion of  Ectosperma  clavata  goes,  it  would  seem  to  apply  to  any 
zoosporiferous  Vaucheria ;  Gotz  does  not  state  why  he  identi- 
fies E.  clavata  with  V.  orthocarpa  Reinsch,  except  that  the  sex- 
ual organs' in  his  plant  agree  with  Reinsch's  description  and 
plate  ;  but  Vaucher  knew  the  zoospores  only. , 

9.  V.  HAMATA   (Vauch.)  De  Candolle,    1805,   p.  63;   Walz, 
1866,  p.    148,   PI.   XII,   figs.   12-16;  Wolle,    1887,  p.    152,   PL 
CXXVIII,  figs.  8-10.     Filaments  40-60  p.  diam.,  oogonia  soli- 
tary,   75-90X60-75  p.,   ovoid    to  convex-concave,   borne  on  the 
shorter  division  of  an  apparently  forking   branch  ;    the  longer 
division  recurved,  bearing  the  hooked  or  circinate  antheridium  ; 
or  an  oogonium  on  each  division,  the  antheridium  between  ;  an- 
theridium   in    a  plane   at   an  angle  to  that  of   the  oogonium  ; 
oospore  closely  filling  the  oogonium,  with  quadruple  membrane 
and  a  dark  brown  or  blackish  central  spot ;  the  membrane  of 
the  oogonium  falling   with  the  oospore,  but   not  gelatinizing  ; 
aplanospores  formed  in  terminal,  somewhat  clavate  sporangia, 
when  ripe  ejected  from  the  latter.     On  moist  ground   or  sub- 
merged.    Washn.,  Cal.  Europe. 

10.  V.  TERRESTRis   (Vauch.)    De    Candolle,    1805,    p.    62 ; 
Walz,  1866,  p.  149,  PL  XIII,  figs.  18  and   19;    Wolle,    1887,  p. 
153,    PL    CXXIX,    figs.    1-8;    P.    B.-A.,    No.    78.     Filaments 
50-80  fj.  diam.;  oogonium  usually  solitary,  85-125X60-100  /*,  lat- 
eral on  a  short  branch,  on  the  summit  of  which  is  the  curved  or 
circinate  antheridium,   about  20  //.  diam.;    oospore   globose   to 
plano-convex,  with -quadruple  membrane  and  numerous  brown- 
ish spots  ;  the  membrane  of  the  oogonium  remaining  attached 
to  the  oospore  and  falling  with  it,  gelatinizing   and  ultimately 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  427 

disappearing.  Though  the  antheridium  is  really  terminal,  it  is 
often  pushed  aside  by  the  oogonium,  and  appears  to  be  lateral, 
below  the  oogonium.  On  moist  ground  or  submerged,  common. 
Greenland,  Mass.,  Neb.,  Cal.  /Europe. 

There  is  considerable  resemblance  between  V.  tcrrcstris  and 
r.  ha  ma  fa,  but  in  the  former  the  fruiting  branch  is  short,  the 
oogonium  practically  sessile  on  the  pedicel  of  the  antheridium  ; 
in  the  latter  the  fruiting  branch  is  usually  longer  and  the  oogo- 
nium and  the  antheridium  are  on  distinct  pedicels,  appearing  as 
if  the  branch  had  forked  ;  the  manner  of  disappearance  of  the 
oogonium  membrane  is  different  ;  aplanospores  are  not  known 
in  / '.  tcrrcstris,  though  it  is  the  commoner  species. 

ii.  V.  GEMINATA  (Vauch.)  De  Candolle,  1805,  p.  62  ;  Walz, 
1866,  p.  147,  PI.  XII,  figs.  7-11  ;  Wolle,  1887,  p.  151,  PI. 
CXXVIII,  figs.  1-3;  P.  B.-A.,  No.  1287.  Filaments  50-100 /x 
diam.  ;  oogonia  2,  70-90X60-75  /x,  ellipsoid-hemispherical  to 
convex-concave,  shortly  stipitate  near  the  end  of  a  short  branch; 
the  antheridium  between  them,  cylindrical,  hooked  or  circinate  ; 
ripe  oospore  brown-spotted  with  triple  membrane,  filling  the 
oogonium  ;  aplanosporangia  either  on  the  same  frond  as  the 
oogonia  or  on  separate  individuals,  aplanospores  120- 200 X 
120-190  /A,  formed  in  ovoid  sporangia  usually  terminating  short, 
lateral  branches,  freed  by  the  dissolution  of  the  membrane  ; 
akinetes  formed  by  the  breaking  up  of  portions  of  the  filaments 
into  short,  thick-walled  cells,  whose  development  varies  consid- 
erably, according  to  circumstances.  Common  in  quiet  or  slowly 
running  water.  Greenland,  Me.,  Mass.,  N.  J.,  Neb.,  Cal. 

Europe. 

Var.  RACEMOSA  (Vauch.)  Walz,  1866,  p.  147  ;  P.  B.-A,  No. 
268.  Oogonia  3-many,  smaller  than  in  the  type,  corymbosely 
arranged  about  the  antheridium.  Vt.,  Mass.,  N.  J.,  Neb., 
Washn.,  Cal.  Europe. 

The  variety  differs  from  the  type  only  by  the  greater  number 
of  oogonia,  and  there  is  no  sharp  division  ;  plants  representative 
of  each  can  often  be  found  in  the  same  tuft ;  the  variety  seems 
to  be  more  abundant  than  the  type.* 

*Gbt/.,  1897,  p.  124,  includes  under  V.  racemosa  what  is  above  included 
under  both  V.  geminata  and  var.  racemosa;  and  at  p.  126  applies  the 
name  V.  geminata  to  what  appears  to  be  quite  a  different  plant,  and  to 
judge  by  the  descriptions  and  figures  a  good  species  ;  but  why  it  should 
bear  the  name  of  V.  geminata  is  not  so  clear.  His  fig.  45.  fhows  a  quite 
regular  ovoid  spore  ;  Vaucher  says  that  the  spores  of  Ectosperma gemin- 
ata "au  lieu  d'etre  arrondies,  representent  une  portion  de  sphere  forte- 


428  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

12.  V.  LONGIPES  Collins,   1907,  p.  201,  PL  LXXVI,  fig.  i. 
Filaments  80-90  p.  diam.,  oogonia  and  antheridia  borne  at  the 
end  of  a  branch  one  to  several  mm.  long,  30-40  //,  diam.  ;  antheri- 
dium  terminal,  cylindrical  or  slightly  tapering,  hooked  or  cir- 
cinate  ;   oogonia  70-85X35-40 /A,  ovoid,  slightly  oblique,  2-4,  on 
pedicels  20-30  /*  diam.,  100-150  p.  long,  arising  a  little  below  the 
antheridium,  and  usually  surpassing  it.     In  brooks  and  pools. 
Cal. 

Somewhat  resembling  V.  geminata,  but  distinct  by  the  very 
long  fruiting  branches,  at  right  angles  to  the  filaments,  as  well 
as  by  the  longer  pedicels  of  the  oogonia. 

13.  V.  GARDNERI  Collins,   1907.  p.  201,  PI.  LXXVI,  figs. 
2  and  3  ;  P.  B.-A.,  No.  1288.    Filaments  50-70/11  diam.,  sparingly 
branched,  branches    mostly  at    right    angles  ;    antheridia    and 
oogonia  borne  on  pedicels  of  about  the  same  size,  60-100  /j.  long, 
15-20  fi  diam.,   arising  from  the  same  point  on   the  filament  ; 
antheridium  solitary,  terminal  on  the  central,  vertical  pedicel, 
less  commonly  2  or  3  on  independent  pedicels,   hooked  or  cir- 
cinate,  tapering  to  10  p.  diam.  ;  oogonia  2-4,  occasionally  more, 
85-95X60-70^,  quite  oblique,  often  concave  on  the  inner  side, 
on  opposite  sides  of  the  antheridium  or  encircling  it,  their  pedi- 
cels at  about  45  degrees  to  the  filament ;   usually  surpassing  the 
antheridium.     In  brooks  and  pools.     Fig.  153.     Cal. 

In  general  arrangement  like  V.  longipes,  but  the  pedicels 
bearing  the  organs  of  fructification  are  placed  directly  on  the 
filament,  radiating  from  one  spot ;  the  oogonia  are  much  more 
oblique,  often  concave  inside. 

Forma  TENUIS  Collins,  1907,  p.  201.  Filaments  30-40/0,  diam.  ; 
antheridia  often  more  numerous  than  the  oogonia  ;  oogonia 
sometimes  single.  With  the  type.  Cal. 

When  in  this  species  two  oogonia  occur  with  one  antheridium, 
there  is  a  certain  resemblance  to  V.  geminata  ;  but  the  slender 
radiate  pedicels  make  it  amply  distinct  ;  the  forms  with  many 
oogonia  and  antheridia  are  quite  unlike  anything  else.  The 
largest  number  of  pedicels  observed  in  a  grdup  is  12,  four  bear- 
ing antheridia,  eight  oogonia. 

ment  e"chancree  a  1'interieur."  Figures  43  and  44,  V.  racemosa,  have 
spores  quite  like  this  description.  The  filaments  of  E.  geminata,  accord- 
ing to  Vaucher,  are  about  half  the  size  of  those  of  E.  sessilis ;  while 
according  to  Gb'tz  the  two  species  are  of  about  the  same  size,  V.  geminata 
slightly  larger.  There  is  no  indication  in  the  descriptions  and  figures  of 
Vaucher  and  Hassall  of  the  lateral  prolongations  of  the  antheridium 
characteristic  of  Gb'tz'  plant.  If  the  latter  were  to  be  identified  with  any 
of  Vaucher's  species,  E:  cm-data  seems  more  probable  than  E.  geminata, 
except  that  it  is  said  to  be  quite  small  in  all  of  its  dimensions. 


THK  GREEN  ALGAE  OF  NORTH  AMERICA  429 

14.  V.  PILOBOLOIDES  Thuret  in  Le  Jolis,    1863,  p.   65,    PI. 
I,  figs.  4  and  5;    Woronin,    1869,  p.  153,  PI.  II,  figs.  18-29;   p- 
B.-A.,    No.  476.       Marine;    filaments  usually  40-60   p   diam., 
sometimes  80 /u. ;  antheridium   terminal,   separated  from  the  fil- 
ament by  an  empty  cell,   cylindrical,   acute,   with  one  or  two 
lateral,  conical  projections  ;    oogonium  terminal,   usually  on   a 
short   branch   near  the  antheridium,   clavate  with   a  spherical 
summit,  up  to  200  p.  diam.  ;   oospore  lenticular  with  thin  mem- 
brane,   150X80-100  p.;    aplanospores    250X80  p.,  formed  at  the 
ends  of  the  branches,  expelled  from  the  sporangium  at  maturity. 
Muddy  and  sandy  places,  below  low  water  mark.     Conn. 

Var.  COMTACTA  Collins,  1900,  p.  13;  P.  B.-A.,  No.  477. 
Tufts  very  densely  matted  ;  oospores  usually  spherical,  occa- 
sionally lenticular ;  oogonia  and  antheridia  scattered  without 
definite  relation  to  each  other.  Salt  marshes,  on  mud  near  high 
water  mark.  Mass.. 

The  dense,  plush-like  coatings  of  this  variety  are  indistin- 
guishable from  V.  Thuretii,  that  grows  in  similar  locations  ;  but 
the  fructification  is  quite  distinct. 

15.  V.    SPHAEROSPORA  Nordstedt,    i878a,    p.    177,   PI.   II, 
figs.  7  and  8  ;  Phyk.  Univ.,  No.  282.     Marine  ;  filaments  25-60 
p.  diam.,  loosely  tufted  ;  antheridium  at  the  somewhat  swollen  end 
of  a  branch,  generally  slightly  curved,  acuminate,  bearing  just 
below  the  summit  two  conical,  subopposite  processes  ;  oogonium 
below  on  the  same  branch,  separated  by  an  empty  cell,  globose 
or  obo void-globose,    105-135  p.  diam.  ;  oospore  green,  with  thin 
membrane,  85-125  p.  diam.,  not  filling  the  oogonium.       Green- 
land. Northern  Europe. 

16.  V.   INTERMEDIA   Nordstedt,    1879,   p.    179,   PL   I,    figs. 
10-16;  Wittr.  &  Nordst.,  Alg.  Exsicc.,  No.  334.     Marine;  fila- 
ments 35-65  p.  diam.  ;  oogonia  subsessile  or  shortly  pedicelled, 
globose  or  ovoid-globose,  90-130  p.  long.,  95-115  p-  wide,  with  one 
short  and  broad  tube  ;  antheridium  single  or  often  two,  20-30  p. 
diam.,   usually  straight  with  rounded,  truncate  apex,  and  2-4 
very  short,  lateral  tubes ;  oospore  globose,  with  thin  membrane, 
85-120   p-   diam.,    almost    filling   the    oogonium.        Greenland. 

Northern  Europe. 

17.  V.  CORONATA  Nordstedt,  1879,  p.  177,  PI.  I,  figs.   1-9; 
Wittr.  and  Nordst.,  Alg.  Exsicc.,  No.  1022.     Marine  ;  filaments 
48-70  p.  diam. ;  oogonia  solitary,  subsessile,  borne  on  the  branches 
bearing   the    antheridia,    more   rarely   on    the   main    filaments, 
obovoid   or   obliquely  ovoid,    125-145  p.  long,    145-180  p.  wide, 
bearing  at  the  top  a  circle  of  3-6  tubes  for  the  entrance  of  the 
spermatozoids ;    oospore  globose  or   subglobose,   115-135X115- 


430          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

145  /j.,  not  quite  filling  the  oogonitim  ;  ripe  oospore  with  occa- 
sional brown  spots,  and  thick,  minutely  pitted  membrane ; 
antheridium  straight  with  rounded  apex,  at  the  end  of  the  branch 
bearing  the  oogonium,  single,  or  oftener  twro,  30-40  //,  diam., 
separated  from  the  branch  by  an  empty  cell ;  with  one  apical 
tube.  Greenland.  Northern  Europe. 

18.  V.  LITOREA  Agardh,  1821,  p.  463;  Nordstedt,  1879,  p. 
1 80,  PI.  II,  figs.  1-6;  Farlovv,  1881,  p.  105;  P.  B.-A.,  No.  166. 
Marine,  dioecious;  filaments  70-95  //,  diam.;  antheridium  at  the 
end  of  a  longer  or  shorter  branch,  supported  by  an  empty  cell, 
cylindrical,  rather  obtuse,  with  2-4  short,  lateral  projections  ; 
oogonium  at  the  extremity  of  a  reflexed  branch,  clavate  or 
obovoid,  about  200  /u,  wide  and  300-400  /j.  long  ;  separated  from 
the  filament  by  a  short,  empty  cell;  oospore  subglobose,  with 
thick  membrane,. 1 80- 250 /A  diam.,  occupying  the  upper  part  of 
the  oogonium.  Mass,  to  N.  J.  Jtnrope. 

A  coarse,  dingy  plant,  with  long  filaments  forming  loose  tufts, 
on  mud  and  gravel  at  low  water  mark.* 

DICHOTOMOSIPHON  Ernst,  1902,  p.  115. 

Frond  filamentous,  inarticulate,  multinucleate,  with  disk- 
shaped  chromatophores  without  pyrenoid ;  filaments  di-poly- 
chotomous,  attached  below  by  slender,  colorless  rhizoids ; 
branches  constricted  at  base  to  about  half  the  diameter  ;  similar 
constrictions  formed  at  intervals  between  the  branchings  ;  mem- 
brane thickened  at  the  constrictions,  often  becoming  brown ; 
starch  accumulation  in  large  quantities  throughout  the  frond. 
Sexual  reproduction  by  terminal  oogonia  and  antheridia ; 
oospore  globose,  with  triple  membrane,  germinating  after  a 
resting  period.  Asexual  reproduction  by  akinetes,  in  the  form 
of  tubercular  swellings  at  the  ends  of  the  branches,  or  oftener 
on  special  lateral  branches,  germinating  after  a  resting  period. 

This  genus  differs  from  Vaiichcria  by  the  true  dichotomous 
branching,  the  peculiar  asexual  reproduction,  the  corymbose 
arrangement  of  the  sexual  organs,  the  presence  of  starch  in 
large  quantity,  and  the  tendency  to  articulation  shown  by  the 
constrictions.  While  the  sexual  fructification,  except  as  to  the 
position  of  the  organs,  is  the  same  as  in  Vaiichcria,  the  vegetative 
characters  are  curiously  like  those  of  some  of  the  marine 
Codiaceae  ;  when  a  Udotea,  for  instance,  is  decalcified,  the  fila- 

*V.  velutina  Wolle,  1887,  p.  153,  is  given  merely  from  older  references. 
According  to  Farlow,  1881,  p.  105,  a  specimen  from  J.  W.  Bailey,  marked 
by  him  V.  velutina,  is  probably  V.  Thuretii  Woronin. 


THE  GREEN  AI.GAE  OF  NORTH  AMERICA  431 

ments  are  in  many  cases  like  those  of  Dichotomosiphon.  As  far 
as  vegetative  structure  is  concerned,  there  would  seem  to  be  a 
definite  phylogenetic  series  from  Dichotomosiplwn  through 
Avrainvillea,  Penicitlits,  Rhipoccphalus  and  Udotca  to  Ifalitncda  ; 
but  while  the  reproductive  organs  of  Dichotomosiphon  are  of  high 
rank,  those  of  Halimcda  are1  much  lower  and  of  a  different  type, 
and  practically  nothing  is  known  as  to  the  reproduction  of  the 
intermediate  genera.  If  any  of  these  genera  should  ever  be 
found  to  have  fructification  resembling  that  of  Dichotomosiphon, 
or  if  sporangia  like  those  of  Halimcda  were  found  in  D.  pusillus, 
the  latter  would  have  to  be  considered  as  the  primary  form  of 
the  Codiaceae  or  at  least  of  the  Udotoideae,  from  which  the 
other  forms  had  developed.  There  is  one  well  known  fresh 
water  species,  to  which  a  marine  form  is  now  doubtfully 

added. 

KEY  TO  THE  SPECIES  OF  DICHOTOMOSIPHON. 

i.     Filaments  40-100  M  diam. ;  freshwater.  i.     D.tuberosus.    ' 

i.     Filaments  10-30  p  diaui. ;  marine.  2.     D.pusillus. 

1.  D.  TUBEROSUS  (A.  Braun)  Ernst,  1902,  p.  115,  Pis.  VI-X  ; 
Vancheria  tuberosa  A.  Braun  in  Kiit/cing,  1856,  p.  23,  PL  L,XV  ; 
Wolle,    1887,  p.    154,   PL  CXXIX,  figs.   9-14,  PL  CXXX  ;  P. 
B.-A.,  No.  764.     Fronds  2-10  cm.  long,  40-110 /*  diam.,  usually 
70-95  p. ;  akinetes  straight  and  elongate  or  clavate  and  curved, 
0.5-5  mm.  long,  200-400  p.  diam.  ;  antheridia  and  oogonia  corym- 
bosely  arranged  at  the  ends  of  the  ultimate  divisions  ;  antheridia 
cylindrical  or  clavate,  more  or  less  incurved,  130-170X35-50^; 
oogonia  globose,  290-320  p.  diam.  ;  oospore  globose,  dark  green, 
250-280 p. diam.     Fig.^  158.     Out.,  Pa.,  Mich.,  111.,  Ga.,  Texas. 

Europe. 

This  species  occurs  in  similar  localities  to  Vaucheria ;  it 
appears  to  be  more  common  in  America  than  in  Europe,  where 
it  is  reported  only  from  Switzerland.  In  P.  B.-A.,  No.  764,  the 
oogonia  are  large  enough  to  be  seen  by  the  naked  eye,  but  are 
erroneously  referred  to  in  the  label  as  "tuber-like  swellings." 
Wolle's  varieties  intermedia  and  minor  are  merely  smaller,  sterile 
forms. 

2.  D.   pusillus  n.  sp.     Filamentis  prostratis,  irregularibus, 
10-30  p  diam.,  hinc  et  illinc  coustrictis,  di-  trichotomis  ;   ramis 
basi  fortiter  constrictis,  apice  et  sub  dichotomiis  saepe  clavifor- 
miter  distentis  ;    ramis  lateralibus  brevibus  et  simplicibus  fre- 
quentis,  sine  ordine  egredientibus,  raro  oppositis. 

Filaments  prostrate,  irregular,  10-30  p  diam.,  here  and  there 


432  TUFTS  COLLEGE;  STUDIES,  VOL.  II,  No.  3 

constricted,  di-  trichotomous  ;  branches  strongly  constricted  at 
the  base,  often  clavately  swollen  at  the  end  or  when  forking  ; 
lateral  branches  also  common,  usually  short  and  simple,  occa- 
sionally opposite.  In  shallow  water,  in  company  with  Bostrychia 
tcnclla  (Vahl)  J.  Ag.,  Lyngbya  confcrvoidcs  Ag.,  etc.  Marine. 
W.  I. 

Nothing  being  known  as  to  its  reproduction,  the  inclusion  of 
this  plant  in  Dichotomosiphon  is  only  provisional ;  in  vegetative 
characters  the  correspondence  is  marked.  It  forms  rather  dense 
mats  on  the  surface  of  the  Bostrychia,  and  appears  to  be  common 
in  Jamaica  and  other  West  India  islands.  The  filaments  in  the 
under  part  of  the  mats  are  colorless  as  in  Vauchcria  ;  at  first 
glance  one  is  reminded  of  the  simpler  forms  of  Udotca  minima 
Ernst,  1904,  PI.  VII,  figs,  i-io,  but  though  part  of  the  plant  is 
colorless,  part  bright  green,  there  is  no  distinction  in  form 
between  the  two  as  in  the  Udotea,  and  both  seem  to  remain 
prostrate.  In  a  few  instances  there  have  been  noticed  short 
simple  branches  in  three  or  four  opposite,  approximate  pairs, 
with  triangular  outline,  like  the  tip  of  a  branch  of  Bryopsis 
p/iunosa,  but  this  may  have  been  accidental ;  there  was  nothing 
to  indicate  that  it  was  a  distinct  erect  growth.  The  constrictions 
at  the  base  of  the  branches  are  strongly  marked,  with  stratified 
thickening  inside  the  wall ;  the  constrictions  in  the  filaments 
may  be  distant,  or  they  may  be  scarcely  more  than  one  diameter 
apart,  when  the  frond  appears  markedly  moniliform. 


The  following  species  was  omitted  from  the  proper  place, 
p.  183  of  this  work. 

ULOTHRIX  SCUTA TA  Jonsson,  1904,  p.  57,  figs.  8  and  9. 
Filaments  attached  by  a  basal  disk,  with  even  or  lobed  margin  ; 
lower  cells  5-6 /u,  diam.,  1-3  diam.  long;  upper  cells  9-16  p.  diam., 
YS-I  diam.  long;  chromatophore  zonate,  not  occupying  the 
whole  length  of  the  cell,  with  one  pyrenoid.  Filaments  with 
more  or  less  distinct  constrictions,  at  intervals  of  about  4  cells. 
Greenland. 

The  basal  disk  characteristic  of  this  species  is  usually  sepa- 
rated from  the  rest  of  the  basal  cell  by  a  sharp  constriction  ;  in 
addition  to  the  disk,  the  filaments  are  often  attached  by  rhi- 
zoids  to  the  substratum,  fronds  of  Spongomorpha. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  433 


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EXSICCATAE. 

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and  Leipzig. 

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Halle. 

Le  Jolis,  A.     Algues  marines  de  Cherbourg.     Cherbourg. 
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Toulouse. 

Tilden,  Josephine  E.     American  Algae,  Centuries  I- VI.     Min- 
neapolis. 
Wittrock,  V.  and  Norstedt,  O.     Algae  aquae  dulcis  exsiccatae. 

Upsala  and  Stockholm. 
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dulcis  exsiccatae.     Lund. 
Wyatt,  Mary.     Algae  Danmonienses.     Torquay. 


456  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 


EXPLANATION   OF   PLATES. 

PLATE  I. 

1.  Botrydiopsis  eriensis,  after  Snow.      1000  X  i. 

2.  Ophiocytium  majus,  after  Nageli.     500  X  i. 

3.  Chlorobotrys  regularis,  after  West.     350  X  i. 

4.  Conferva  bombycina,  after  West.     750  X  i. 

5.  Botrydium  granulatum,  after  West.      15  X  i. 

6.  Characiopsis  minuta,  after  West.     350  X  i. 

7.  Zygneraa  stellinum,  with  spores,  after  West.     300  X  i. 

8.  Spirogyra  protecta,  with  spores,  after  Petit.     250  X  i. 
ga.  Debarya  glyptosperma,  conjugating  ;  gb,  with  ripe  spores  ; 

after  De  Bary.     250  X  i. 

10.  Zygogonium    ericetorum,    conjugating,    after     De    Bary. 

400  X  i. 

11.  Gonatonema  ventricosum,  with  spores,  after  West.  800X1. 

PLATE  II. 

12.  Mougeotia  viridis,  with  spores,  after  De  Bary.      1000  X  i. 

13.  Chlamydomonas  angulosa,  after  Dill.      1000  X  i. 

14.  Haematococcus  pluvialis,  after  Hazen.     700  X  i. 

15.  Chlorogonium  euchlorum,  after  Stein.      1000  X  i. 

1 6.  Goniurn  pectorale,  after  Migula.     600  X  i. 

17.  Pandorina  Morum,  after  Pringsheim.     700  X  i. 

1 8.  Pleodorina  illinoisensis,  after  Kofoid.     500  X  i. 

PLATE  III. 

19.  Platydorina  caudata,  face  view,  after  Kofoid.     500  X  i. 

20.  Platydorina  caudata,  side  view,  after  Kofoid.     300  X  i. 

21.  Eudorina  elegans,  after  Gbbel.     300  X  i. 

22.  Volvox  globator,  after  Oltmanns.     300  X  i. 

23.  Palraella  miniata,  after  Nageli.     400  X  i. 

PLATE  IV. 

24.  Botryococcus      Braunii,     colony     dividing,     after  ,  West. 

600  X  i. 

25.  Ineffigiata  neglecta,  after  West.     700  X  i. 

26.  Tetraspora  lubrica,  after  Nageli.     400  X  i. 


THE  GREEN  ALGAE  OP  NORTH  AMERICA  457 

27.  Apiocystis  Bramiiana,  after  Nageli.     250  X  i. 

28.  Palmodactylon  varium,  young  colony,  after  West.   125  X  i. 

29.  Prasinocladus  subsalsus,  after  Davis.     600  X  r. 

30.  Collinsiella  tuberculata,  after  Setchell.     200  X  i. 

31.  Chlorococcum  humicola,  after  Nageli.     300  X  i. 
323.  Trochiscia  reticularis,  after  West.     400  X  i. 
32b.  Trochiscia  hirta,  after  West.     300  X  i. 

33.  Chlorochytrium  Leranae,  cells  in  different  stages,  in  tissue 

of  L,emna,  after  Klebs.     200  X  i. 

34.  Rhodochytrium  Spilanthidis,  irregularly  shaped  cell,  after 

Lagerheim.     200  X  i. 

35.  Chlorocystis    Cohnii,    on     Enteromorpha,    after     Moore. 

1000  X  i. 

PLATE  V. 

36.  Characium  gracilipes,  after  Lambert.     500  X  i. 

37.  Codiolum  gregarium,  after  A.  Braun.     100  X  i. 

38a.  Protosiphon  botryoides,  vegetative,  after  Klebs.     50  X  i. 
38b.   Protosiphon   botryoides,   with    aplanospores,    after    Klebs. 
100  X  i. 

39.  Eremosphaera  viridis,  section  of  cell,  after  Moore.     2ooX  i . 

40.  Excentrosphaera    viridis,    section   of    cell,    after    Moore. 

1000  X  i. 

41.  Zoochlorella  conductrix,  in  Hydra  viridis,  after  Beyerinck. 

600  X  i. 

42.  Rhaphidium  falcatum  var.  fusiforme,  group  of  individuals, 

after  Nageli.     300  X  i. 

43.  Palmellococcus  miniatus,  with  aplanospores,  after  Choclat. 

800  X  i. 

44.  Oocystis  solitaria,  after  West.     800  X  i. 

45.  Chodatella  citriformis,  after  Snow.      1000  X  i. 

46.  Nephrocytium  Agardhianum,  mother  and  daughter  cells, 

after  Nageli.     1000  X  i. 

47.  Tetraedron  trigonum,  front  and  side  views,  after  Nageli. 

800  X  i. 

48.  Cerasterias  raphidioides,  after  Reinsch.     1000  X  i. 

PLATE  VI. 

49.  Thamniastrum  cruciatum,  after  Reinsch.     500X1. 


458  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

50.  Schizochlamys  gelatinosa,  recently  divided  cell,  after  West. 

500  X  i. 

51.  Elakatothrix  americana,  mother  and  daughter  cells,  after 

Snow.     800  X  i. 

52.  Hormotila  mucigena,  after  West.     500  X  i. 

53.  Scenedesmus  obliquus,  after  Nageli.     500  X  i. 

54.  Crucigenia  rectangularis,  after  West.     600  X  i. 

55.  Selenastrum  minutum,  after  Nageli.     1000  X  i. 

56.  Kirchneriella  lunaris,  after  Bohlin.     800  X  i. 

57.  Coelastrum  cambricum,  after  West.     800  X  i. 

58.  Sorastrum  spinulosura,  after  Nageli.     500  X  i. 

59.  Dictyosphaerium  Ehrenbergianum,  after  Nageli.    600  X  i. 

60.  Dimorphococcus  cordatus,  after  Wolle.     500  X  i. 

61.  Dictyocystis  Hitchcockii,  after  Wolle.     600  X  i. 

62.  Hydrodictyon  reticulatum,   young  colony  in  mother  cell, 

after  Klebs.     100  X  i. 

63.  Pediastrum  Boryanum,  after  Nageli.     800  X  i. 

64.  Uiothrix  zonata,  vegetative,  after  Hazen.      300  X  i. 

65.  Hormospora  purpurea,  after  Wolle.     300  X  i. 

PLATE  VII. 

66.  Uronema  confervicola,  after  Lagerheim.     800  X  i. 

67.  Schizomeris  Leibleinii,  after  Hansgirg.     60  X  i. 

68.  Microspora  tumidula,  akinetes  in  formation,  after  Hazen. 

500  X  i. 

69.  Stichococcus  bacillaris,  after  Nageli.     800  X  i. 

70.  Enteromorpha  erecta,  surface  view,  after  Collins.     200X1. 

71.  Ilea  fulvescens,  surface  view,  after  Collins.     200  X  i. 

72.  Monostroma  fuscum,  cross  section,  after  Collins.     200  X  i. 

73.  Protoderma     viride,     surface     view,     after      Rabenhorst. 

600  X  i. 

74.  Radiofilum  apicttlaturn,  surface  view,  after  Bohlin.    800X1 

75.  Ulva  L,actuca,  cross  section,  after  Thuret.     300  X  i. 

76.  Schizogonium     crenulatum,     surface    view,     after    Gay. 

1000  X  i. 

77.  Prasiola  crispa,  mature  frond,  after  Oltmanns.     100  X  i. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  459 

78.  Gayella  polyrhiza,  multiseriate  stage,  after  Rosenvinge. 

500  X  i. 

79.  Gayella     polyrhiza,    with    rhizoids,     after    Rosenvinge. 

500  X  i. 

80.  Cylindrocapsa  geminella,  with  oogonia,  after  Hansgirg. 

300  X  i. 

PLATE  VIII. 

81.  Oedogonium  fragile,   with  oogonia  and  antheridia,  after 

Wittrock.     400  X  i. 

82.  Bulbochaete   intermedia,  with  oogonia  and  dwarf  males, 

after  Wittrock.     300  X  i. 

83.  Microthamnion  Kuetzingianum,  after  Hazen.     700  X  i. 

84.  Stigeoclonium  lubricum,  after  Hazen,  400  X  i. 

85.  Chaetophora  elegans,  after  Hazen.     400  X  i. 

86.  Chlorotylium  cataractarum,  branching  filament,  after  Rab- 

enhorst.     400  X  i. 

87.  Pseudendoclonium  submarinum,  after  Wille.     1000   X   i. 

88.  Endoclouium  Moebiusianum,  portion  of  disk,  after  Mobius. 

600  X  i. 

PLATE  IX. 

89.  Draparnaldia  glomerata,  after  Hazen.     300  X  i. 

90.  Pilinia  Morsei,  after  Collins.     400  X  i. 

91.  Gongrosira  deBaryana,  after  Rabenhorst.     300  X  i. 

92.  Ochlochaete  ferox,  after  Huber.     300  X  i. 

93.  Dermatophyton  radians,  oo  and  in  shell  of  turtle,  after 

Potter.     500  X  i. 

94.  Epicladia  Flustrae,  after  Reinke.     400  X  i. 

PLATE  X. 

95.  Pringsheimia   scutata,  mature   frond   with   spores,   after 

Reinke.     600  X  i. 

96.  Chaetopeltis    americana,    portion    of    disk,  after   Snow. 

400  X  i. 

97.  Arthrochaete  penetrans,  after  Rosenvinge.     500X1. 

98.  Chaetobolus  gibbus,  after  Rosenvinge.     300X1. 

99.  Diplochaete  solitaria,  by  L/ambert.     400  X  i. 

100.  Endoderma  Wittrockii,  after  Hazen.     400  X  i. 

101.  Acrochaete   repens,    with   sporangia,    after   Pringsheim. 

500  X  i. 


460    TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

PLATE  XI. 

102.  Ulvella  lens,  after  Huber.     300  X  i. 

103.  Gloeocystis  gigas,  after  West.     500  X  i. 

104.  Chaetosphaeridium  Pringsheimii,  after  Klebahn.     SooX  i. 

105.  Urococcus  Foslieanus,  after  Foslie.     800  X  i. 

106.  Pleurococcus  vulgaris,  after  West.      1000  X  i. 

107.  Palmodictyou  viride,  after  West.     400  X  i. 

108.  Bolbocoleon    piliferum,    with    sporangia,    after    Hauck. 

600  X  i. 

109.  Gloeotaenium     L,oitlesbergerianum,    after     Stockmayer. 

500  X  i. 

PLATE  XII. 
no.     Coleochaete  divergens,  with  oogonia,    after  Pringsheim. 

200  X  i. 
nr.     Tellamia  contorta,  cross  section,  after  Batters.     200  X  i. 

112.  Tellamia  contorta,  surface  view,  after  Batters.     300  X   i. 

113.  Pithophora   oedogonia,    with    akinetes,    after    Wittrock. 

40  X  i. 

114.  Nylandera  tentaculata,  after  Hariot.     300  X  i. 

115.  Chaetomorpha    aerea,    basal    and    upper    portions,    after 

Hauck.     40  X  i. 

116.  Herposteiron  confervicola,  after  Hazen.     800  X  i. 

117.  Trentepohlia  Wainoi,  after  Hariot.     250  X  i. 

118.  Dactylothece  confluens,  after  Nageli.      1,000  X  i. 

119.  Rhizoclonium  hieroglyphicum,  after  Stockmayer.    300X1. 

PLATE  XIII. 

120.  Pseudodictyon  geniculatum,  surface  view,  after  Gardner. 

500  X  i. 

121.  Endophyton   rainosum,  section  of   host  with  endophj'te, 

after  Gardner.     300  XL 

122.  Gloiococcus  mucosus,  after  West.     400  X  i. 

123.  Cephaleuros  Mycoidea,  after  Karsten.     200  X  i. 

124.  Cladophora  glomerata,  after  West.      100  X  i. 

PLATE  XIV. 

125.  Anadyomene  stellata,  after  Oltmanns.      10  X  i. 

126.  Spongomorpha  spinescens,  after  Kjellman.     40  X  i. 

127.  Cystodictyon  pavonium,  by  Lambert.      10  X  i. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA  461 

128.  Boodlea  compacta,  after  Brand.     40  X  i. 

129.  Cladophoropsis  membranaceus,  after  Borgesen.     20  X  i. 

130.  Halicystis  ovalis,  after  Saunders.     2X1. 

PLATE  XV. 

131.  Acetabularia  crenulata,  group  of  individuals,  after  Har- 

vey.    2X1. 

132.  Microdictyon  Agardhianum,  after  Montague.     20  X  l. 

133.  Hormiscia    penicilliformis,     filament,    after    Areschoug, 

200  X  i.     Zoospore,  after  Areschoug.     1000  XL 

134.  Struvea  anastomosans,  after  Harvey.     3X1. 

135.  Gomotia   polyrhi/.a,  with    sporangium,  after  Bornet  and 

Flahault.     300  X  i. 

136.  Chamaedoris  aunulata,  after  Harvey,      i  X  i. 

137.  Dictyosphaeria  favulosa,  group  of  individuals,  after  Har- 

vey.    10  X  i. 

138.  Valonia  utricularis,  after  Schmitz.      10X1. 

PLATE  XVI. 

139.  Siphonocladus  rigidus,  after  Howe.     20  X  i. 

140.  Chalmasia  antillarum,  stipe  and  disk,  5X1;  details  of 

base  of  disk,  20  and  40 'X  i,  after  Solms. 

141.  Sphaeroplea   annulina,    with    oospores,   after   Hansgirg. 

200  X  i. 

142.  Dasycladus  claveformis,  after  Hauck.     i  X  i. 

143.  Neomeris  annulata,  group  of  individuals,  after  Cramer. 

i  X  i. 

144.  Codium     tomentosum,     utricle    and    sporangium,     after 

Thuret.     75  X  i. 

145.  Batophora  Oerstedi,.  group  of  individuals,  after  Harvey. 

i  X  i. 

146.  Cymopolia  barbata,  after  Harvey,     i  X  i. 

147.  Avrainvillea  levis,  after  Howe,     i  X  i. 

148.  Acicularia  Schenckii,  disk  from  above,  5X1;  contents 

of  sporangium,  10  X  i,  after  Borgesen. 

PLATE  XVII. 

149.  Penicillus  capitatus,  after  Harvey,     i  X  i. 

150.  Rhipocephalus  Phoenix,  after  Harvey.     2X1. 


462  TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

151.  Cladocephalus  luteo-fuscus,  filaments  of  cortex,  after  Bor- 

gesen.     100  X  i. 

152.  Derbesia  marina,   frond  with  sporangia,  after  Saunders. 

40  X  i  ;  zoospore,  after  Solier.     300  X  i. 

153.  Vaucheria  Gardneri,  after  Gardner.      100  X  i. 

154.  Udotea  cyathiformis,  after  Harvey,     i  X  i. 

155.  Bryopsis  plumosa,  after  Kiitzing.     20  X  i. 
156:    Halimeda  Opuntia,  after  Gobel.     i  X  i. 

157.  Phyllosiphon  Arisari,  surface  view,  after  Kiihn.     40  X  i. 

PLATE  XVIII. 

158.  Dichotomosiphon  tuberosus,  with  oogonia  and  antheridia, 

after  Ernst.     50  X  i. 

159.  Ostreobium  Quekettii,  after  Bornet  and  Flahault.    25oX  i. 

160.  Caulerpa  prolifera,  after  Reinke.     i  X  i. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA 


463 


INDEX. 

Synonyms  are  printed  in  italics.     The  number  of  the  page  at  which  a 
species  or  genus  is  described  is  in  full-face  type. 


Acanthococcus. 

aciculiferus,  145. 

argutus,  146. 

asper,  145. 

grannlafns,  145. 

nirtus,  145. 

obtitsus,  146. 

reticnlaris,  145. 

spor  aides,  145. 
Acetabularia,  377. 

caliculus,  378. 

camibica,  378. 

creuulata,  378,  380. 

Farlowii,  379. 

polyphysoides,  379. 
f.  deltoidea,  379. 

pusilla,  379. 

Suhrii,  378. 
Acetabuluin. 

Farloivii,  379. 

polyphysoides,  379. 
f.  deltoideum,  379. 

p  ii  si  Hum,  379. 
Acicularia,  380. 

Schenckii,  380. 
Acroblaste. 

Reinschii,  292. 

sp.,  293. 
Acrochaete,  282. 

parasitica,  282. 

repens,  282. 
Acrosiphonia,  331,  357. 

inciin-a,  357. 

hystri.v,  358. 
/.  littoralis,  358. 
/.  typica,  358. 
Aegagropila,  331, 332, 349. 356, 362. 

Montagnei,  350. 
Akinetes,  101. 
Akontae,  90. 
Anadyomene,  365. 

flabellata,  365. 

Menziesii,  365. 

stellata,  365. 
f.  lu.vurians,  365. 
/.  normalis,  365. 
Androgynia. 

e  china  to.,  252. 
Androsporangiutn,  224. 
Androspore,  224. 


Antheridium  exterius,  249. 
Antheridiuni  interius,  260. 
Aphanochaete,  311. 

globosa,  281. 

repens,  311. 

vermiculoides,  311. 
Apiocystis,  140. 

Brauniana,  140. 

elongata,  140. 
Aplanogametes,  101. 
Aplanospores,  101. 
Araucarioideae,  410. 
Arisaeuia. 

triphyllurn,  408. 
Arisaruui. 

vulgare.  408. 
Arthrochaete,  290. 

penetrans,  290. 
Avrainvillea,  87,  389,  394,  431. 

asarifolia,  390. 

comosa,  391. 

levis,  390. 

longicaulis,  390,  391. 

Mazei,  391. 

nigricans,  390. 
f.  fulva,  390. 

Rawsoni,  390. 

sordida,  390. 
Bangia. 

fusco-purpurca, 185,  209,  368. 

laetevirens.  187. 
Batophora,  383. 

Oerstedi,  383,  384. 

v.  occidentalis,  384. 
Batrachospermum,  314. 
Bibliography,  84. 
Blodgettia. 

Borneti,  348. 

confervoides,  348. 
Bolbocoleon,  86.  283,  311. 

piliferum,  283. 
Boodlea,  366. 

composita,  367. 
Bostrychia. 

tenella,  432. 
Botrydiaceae,  97. 
Botrydiopsis,  93. 

arhiza,  93. 

eriensis,  93. 

oleacea,  93. 


464 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 


Botrydium,  97. 

granulatum,  98,  154, 

Wallrothii,  98.  154. 
Botryococcus,  137. 

Brauuii,  137,  138. 
Botryophora. 

Conquerantii,  383. 

occidentalism  383. 
Brauchipus. 

vernalis,  151. 
Brasenia,  88. 
Bryoideae,  410. 
Bryopsidaceae,  402. 
Bryopsis,  87,  402. 

corticulans,  404. 

Duchassaingii,  403. 

foliosa,  405. 

Harveyana,  405,  406. 

hypnoides, '402,  403. 

Leprieurii,  404  405. 

my ura,  405. 

pennata,  405. 

pennatula,  405. 

plutnosa,  402,  403,  404,  405,  406, 

432. 

v.  rainulosa,  404. 
v.  secunda,  405. 

ramulosa,  404. 

simplex,  407. 
Bulbochaete.  266. 

angulosa,  270. 

Brebissonii,  268. 

Canbyi,  271. 

crassiuscula,  271. 

crenulata,  269. 

dispar,  270. 

dumosa,  273. 

elachistandra,  270. 

gigantea,  271. 

insignis,  274. 

v.  reticulata.  275. 

intermedia,  268. 

f.  supramediana,  269. 

minor,  275 

niirabilis,  272. 

monile,  272. 

nana,  272. 

Nordstedtii,  269. 

polyandria,  270. 

pygmaea,  273. 

rectangularis,  273,  274. 
v.  hiloensis,  274. 

repanda,  274. 

rhadinospora,  274. 

setifera,  271. 

subsimplex,  273. 

varians,  274. 

v.  subsimplex,  273. 


Calothrix,  152,  293,  294. 
parasitica,  284. 
pulvinata,  293. 
scopuloruui,  152. 
Castagnea. 

virescens,  284. 
Caulerpa,  91,  409. 
ambigua,  421. 
Ashmeadi,  414. 
asplenioides,  414. 
clai'ifera,  419. 
crassifolia,  413. 
f.  laxior,  413, 
f.  mexicana,  413. 
f.  pectiuata,  414. 
f.  typica,  413. 
cupressoides,  416. 
.v.  disticha,  418. 
v.  ericifolia,  417. 
v.  Lycopodium,  417. 
f.  alternifolia,  417. 
f.  elegans,  418. 
f.  intermedia,  418. 
f.  plumarioides,  417. 
f.  typica,  418. 
v.  inauimillosa,  417. 
f.  nuda,  417. 
f.  typica,  417. 
v.  serrata,  417. 
v.  Turneri,  417. 
v.  typica,  417. 
fastigiata,  411. 

v.  confervoides,  412. 
Freycinetii,  415. 
v.  de  Boryana,  416. 

f.  occidentals,  416. 
v.  pectinata,  416. 
v.  typica,  416. 
f.  angusta,  416. 
f.  lata,  416. 
lanuginosa,  415. 
Lycopodium  415. 

v.  delicatula,  415. 
inacrodisca,  421. 
mexicana,  413. 
paspaloides,  418. 
v.  laxa,  419. 
v.  typica,  419. 

f.  compres.sa,  419. 
f  flabellata,  419. 
f.  paspaloides,  419. 
f.  phloeoides,  419. 
v.  Wurtlemanni,  419 

f.  phyllophlaston,  419. 
peltata,  421. 
v.  typica,  421. 

f.  imbricata,  421. 
pinnata,  413. 


THE  GREEN  ALGAE  OP  NORTH  AMERICA 


465 


f.  laxior,  413. 
f.  pectinata,  414. 
phyllophlaston,  419. 
pluinaris,  414. 
f.  brevipes,  415. 
f.  Farlowii,  415. 
/.  longipes,  415. 
f.  long  i  set  a,  415. 
prolifera,  413. 
f.  obovata,  413. 
f.  zosterifolia,  413. 
pusilla,  412. 
racemosa,  419. 
v.  clavifera,  420. 

f.  uiacropbysa,  420. 
v.  gracilis,  421. 
v.  laetevireus,  420. 

f.  typica,  421. 
v.  Lamourouxii,  421. 
v.  occidentalis,  420. 
v.  uvifera,  420. 

f.  condensata,  420. 
sertularioides,  414. 
f.  brevipes,  415. 
f.  Farlowii,  415. 
f.  longipes,  415. 
f.  longiseta,  415. 
taxifolia,  414. 
verticillata,  412. 

f.  charoides,  412. 
Webbiana,  412. 
f.  disticba,  413. 
f.  tomentella,  413. 
Caulerpaceae,  408. 
Cephaleuros,  320. 
Mycoidea,  321. 
Cerasterias,  166. 
raphidioides,  166. 
v.  iuaequale,  166. 
v.  incrassatum,  166. 
staurastroides,  166. 
Ceratophyllum,  147. 
Chaetobolus.  289,  290. 

gibbus,  289. 
Chaetomorpha,    87,    181,    182,   288, 

322,  326,  339,  350,  358. 
aerea,  324. 
antennina,  324. 
brachygona,  325. 
californica,  325. 
cannabina,  325.       • 
chelonum.  326. 
clavata,  323. 

v.  torta,  323. 
intestinalis,  326. 
lanosa,  328. 


Lin u in,  325. 

longiailiciilata,  325. 

Olneyi,  325. 

media,  326. 

ruelagonium,  290,  323. 
f.  rupincola,  323.  324. 
f.  typica,  323,  324. 

pacifica,  324. 

Picquotiana,  324. 

saccata,  326. 

submarina,  328. 

siiloria,  325. 

tenuissima,  326. 

tortuosa,  328. 
Chaetopeltis,  288,  289. 

ainericana,  289. 

minor,  289. 

orbicularis,  289. 
Chaetophora,  295,  302. 

attenuata,  296. 

cornu-damae,  297. 

elegans,  295,  296. 

endivaefolia,  297. 

incrassata,  296. 

inaritima,  293. 

pel  lieu  la,  294. 

pisiformis,  296. 
Chaetophoraceae,  275. 
Chaetopteris. 

plumosa,  147. 
Chaetosphaeridium,  281,  311. 

globosum,  281. 

Pringsheimii,  281. 
Chalmasia,  380. 

antillana,  380. 
Chamaedoris,  371,  375. 

annulata,  375. 
Chara,  313. 
Characeae,  80. 
Characiopsis,  99,  149. 

acuta,  99. 

ellipsoidea,  100. 

minuta,  99. 

subulata,  100. 
Characiutn,  99,  149. 

acuminatum,  151. 

acutum,  99. 

ambiguum,  150. 

cylindricum.  151. 

De  Baryanum,  150. 

gracilipes,  151. 

heteromorphum,  150. 

minutum,  99. 

Naegelii,  150. 

obtusum,  150. 

Pringsheimji,  151. 


466          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 


sessile,  149. 

Sieboldii,  150. 

stricturu,  150. 

subulatum,  100. 
Charoideae,  410. 
Chlamydomonadaceae,  128,  131. 
Chlatnydomonas,  83,  128. 

angulosa,  129. 

communis,  129. 

globosa,  129. 

gracilis,  129. 

tnucicola,  129. 

nivalis,  129. 

Reinhardi,  129. 

Steinii,  129. 
Chlorella,  157,  305. 
Chlorobotrys,  95. 

regularis,  95. 
Chlorochytriuni,  86,  146,  148. 

Archerianum,  147. 

deruiatocolax,  14?. 

inclusum,  14f. 

Kuyanum,  14<T. 

Lemnae,  146. 

Schmitzii,  14?. 
Chlorococcutn,  143,  157,  305. 

endoziocum,  144. 

hurnicola,  143. 

infusionum,  143. 

natans,  144. 
Chlorocystis,  148. 

Cohnii,  148. 
Chlorodesmis. 

comosa,  391. 

vaucheriaefonniSt  406. 
Chlorogoniutn,  130. 

euchlorum,  130. 
Chloromonadaceae,  92. 
Chlorophyceae,  91,  100. 
Chlorosphaera,  305. 

lacustris,  305. 

parvula,  305. 
Chlorotheciaceae,  99. 
Chlorotyliutn,  291. 

cataractaruni,  291. 
Chodatella,  160. 

citriformis,  160. 
Chorda. 

filum,  282. 
Chroolepus. 

abietinum,  317. 

aureum,  316. 

lolithus,  319. 

lageniferum,  318. 

moniliforme,  320. 

odor  a  turn,  319. 


rigidulum,  320. 
nmbrinuin,  319,  320. 
Cladocephalus,  394,  396. 
luteo-luscus,  39?. 
scoparius,  396. 

Cladophora,    83,    86,    87,    288,   326, 
327,  331,  357,  358,  362,  363, 
366,  367,  376. 
aegagropila,  355. 
alaskana,  357,  358. 
albida,  336,  337,  340. 

v.  refracta,  336,  344. 
amphibia,  349. 
anastomosans,  376. 
arcta,  359. 

v.  centralist  360. 

f.  conglutinata,  359. 

f.  debilis,  358. 

f.  pulvinata,  360. 
Bertolonii. 

v.  hatnosa,  344. 
brachyclados,  33f. 
brachyclona,  341. 
callicoma,  jjo,  352. 
canalicularis,  351. 

v.  genuina,  352. 
cartilaginea,  346,  362. 
eaten ata,  34<T- 
catenifera,  347. 
Chamissonis,  360. 
coalita,  361. 
coluttt&iana,  349. 
composita,  367. 
constricta,  339. 
crispata,  354. 

f.  longissitna,  355. 

f.  subsiinplex,  355. 

v.  virescens. 
f.  thermalis,  354. 

f.  vitrea.  354. 
crispula,  339. 
crucigera,  340. 
crystaliina,  342. 
dalmatica,  342. 
declinata,  351. 

v.fluitans,  351. 
delicatula,  337,  338. 
diffusa,  346. 
Engelmanni,  364. 
expansa,  198,  340,  343. 

v.  glomerata,  341. 
fascicularis,  345. 
flavescens,  338. 
flexuosa,  336,  339,  342,  344. 

f.  densa,  336,  340. 

f.floridana,  337. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA 


467 


fluitans,  352. 

fracta,  332,  339,  341,  353,  355. 

v.  calcarea,  353. 

f.flavescens,  339. 

f.  gossypina,  353. 

f.  reflexa,  353. 

f.  rigidula,  353. 

f.  strepens,  353. 

v.  subsitnplex,  353. 
fuliginosa,  348. 
glaucescens,  199,  336,  340. 
glonierata,  332,  350,  351. 

v.  callicotna. 

f.  boreali-americana,  352. 
f.  minnesotana,  353. 

v.  clavata,  350. 

v.fasciculata,  350. 

v.  macrogonya,  352. 

f.  uiucosa,  351. 

7'.  parvula,  351. 

f.  rivularis,  351. 
gracilis,  337,  339,  340,  342. 

f.  australis,  343. 

f.  elongata,  343. 

f.  expansa,  343. 

f.  subflexuosa,  343. 

v.  tennis,  343 

v.  vadormn,  343. 
grauiinea,  347. 
hanwsa,  344. 
hirta,  340,  342,  343. 
holsatica,  355. 
Howei,  349. 
Hutchinsiae,  345. 

v.  distans,346. 
hystrix,  358. 
insignis,  355. 
intertexta,  350. 
Kuetzingiana,  352. 
laetevirens,  340,  342,  345. 
lanosa,  357,  358. 

v.  uncialis,  357. 
luteola,  338. 
macrogonya,  352. 
Magdalenae,  348. 
incinbranacea,  362. 
microcladioides,  344. 
Morrisiae,  356. 
nitida,  338. 
nitidissima,  342. 
oligoclona,  353. 

v.  Flotowiana,  354. 
ovoidea,  346. 
pellucida,  347. 
polaris,  361. 
polyacantha,  337. 


prolifera,  347,  348.  ' 

refracta,  336,  344,  351. 

repens,  349. 

Rudolphiana,  336. 

rupestris,  339,  346. 

saxatilis,  360. 

scitula,  341. 

scopaeforviis,  361. 

secunda,  355. 

sericea,  342, 

Stiuipsoni,  338. 

strepens,  353. 

trichocoina,  338. 

trichotoma,  349. 

trinitatis,  356. 

uberrima,  356. 

uncialis,  359. 

utriculosa,  346. 

vadorum,  343. 

virgatula,  337. 
Cladophoraceae,  181,  321. 
Cladophoropsis,  362. 

uienibrauaceus,  362,  375. 
Classification,  89. 
Closterium. 

cuspid atum,  95. 
Coccocladus. 

occidentalism  383. 

v.  laxus,  383. 
Codiaceae,  386. 
Codioideae,  386. 
Codiolum,  86,  87,  151. 

gregariutn,  152. 

f.  intermedium,  152. 

intermedium,  152. 

longipes,  153. 

Petrocelidis,  152. 

pusillum,  153. 
f.  americanum,  153. 
f.  loneipes,  153. 
f.  typicum,  153. 
Codium,  386. 

adhaerens.  387. 

dtfforme,  387. 

elongatum,  388. 

isthmocladum,  388. 

Lindenbergii,  388. 

mamillosum,  388. 

mucronatum,  389. 
v.  californicum,  389. 
v.  novae  zelandiae,  389. 

repens,  388. 

Rilteri,  387. 

tenue. 
v.  repens,  388. 

tomentosum,  388. 


468 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 


Coelastrum,  If  1,  305. 

cambricum,  173. 

microporum,  If 2. 
v.  speciosum,  172. 

proboscideum,  172. 

reticulatutn,  173. 

sphaericum,  172. 
Coleochaetaceae,  312. 
Coleochaete,  281,  312. 

divergens,  314. 
v.  minor,  314. 

irregularis,  313. 

Nitellarum,  313. 

orbicularis,  314. 

pulvinata,  314,  315. 

scutata,  314. 

soluta,  313. 
Collinsiella,  141. 

tuberculata,  141. 
Conferva,  93,  95,  181,  192. 

aerea,  324. 

amoena,  193. 

antillarum,  97, 

bombycina,  96. 
f.  minor,  96. 
f.  tenuis,  96. 

brachyarthra,  324. 

cartilaginea,  361. 

centrifuga,  97. 

Chamissonis,  360. 

coalita,  361. 

collabens,  369. 

diffusa,  346. 

duriuscula,  358. 

fascicularis,  345. 

floccosa,  194. 

glomerata,  345. 

Linum,  325. 

melagonium,  323. 

Mertensii,  360. 

minor,  97. 

pachyderma,  193. 

saxatilis,  360. 

scitula,  341. 

serpens,  97. 

sesquipedalis,  97. 

umbilicata,  366. 

utriculosa,  97. 

viminea,  360. 

Youngana,  368. 
Confervaceae,  92. 
Confervales,  91,  92. 
Conjugates,  90,  91,  101. 
Conjugata,  107. 

longata,  118. 
Corniculatae,  422. 


Corona  inferior,  378. 
Corona  superior,  378. 
(Tra  terosperm  inn,  121. 

laetevirens,  125. 
Crucigenia,  170. 

apiculata,  170. 

crucifera,  170. 

rectangularis,  171. 
Cruoria,  147. 
Cyclops,  150. 
Cylindrocapsa,  222. 

amoena,  222. 

geminella,  222. 
Cylindrocapsaceae,  222. 
Cymopolia,  382. 

barbata,  383. 
•  mexicana,  383. 

rosarium,  383. 
Cystococcus,  305. 

hitviicola,  143. 
Cystodictyon.  366. 

pavonium,  366. 
Dactylococcus. 

De  Baryanus,  150. 
Dactylothece,  307. 

confluens,  307. 
Dasycladaceae,  377. 
Dasycladus,  383. 

clavaeformis,  383. 

occidentalis,  384. 
Debarya,  119. 

glyptosperma,  120,  124. 
Derbesia,  406. 

Lamourouxii,  407. 

marina,  407. 

tenuissima,  406,  407. 

vaucheriaeformis,  406. 
Derbesiaceae,  406. 
Dermatophyton,  285. 

radians,  285. 

radicans,  285. 
Desmidiaceae,  80,  101. 
Desmotrichuni. 

undulatum,  279. 
Dichotomosiphon,  394,  430. 

pusillus,  431. 

tuberosus,  431. 
Dictyocystis,  175. 

Hitchcockii,  175. 
Dictyosiphon,  284. 
Dictyosphaeria,  367. 

favulosa,  367. 
Dictyosphaerium,  173. 

Ehrenbergianum,  174. 

Hitchcockii,  175. 

pulchellum,  174. 


THE  GRKKN  ALGAE  OF  NORTH  AMERICA 


469 


reniforme,  174. 
Dimorphococcus,  174. 

cordatus,  174. 

lunatus,  175. 
Dioecious,  224. 
Diplochaete,  277. 

lamellosa.  278. 

simplex,  278. 

solitaria,  278. 
Diplo/yga,  107. 

Dissepiment  inferior,  267. 

Dissepiment  median,  267. 

Dissepiment  superior,  267. 
Distribution,  81. 
Division  horizontal,  225. 
Division  vertical,  225. 
Draparnaldia,  300,  302. 

acuta,  303. 

glomerata,  303. 

platyzonata,  304. 

plumosa,  303. 
Dwarf  males,  224. 
Ecballocystis. 

japonica,  141. 

pulvinata,  141. 

Wi  lie  ana,  141. 
Ectocarpus,  293. 

fasciculatus,  341. 
Ectosperma. 

clavata,  426. 

cruciala.  428. 

geminata,  427. 

sessilis,  428. 
Elachista. 

fucicola,  279. 
Elakatothrix,  167. 

arnericana,  167. 
Ellipsospora,  235,  247,  260,  272. 
Elodea, 147. 
Endocloniurn,  284. 

Moebiusiauum,  285. 
Endoderma,  278. 

perforans,  279. 

Pithophorae,  280. 

polymorphuni,  280. 

viride,  279. 

Wittrockii,  279. 
Endophyton,  282,  283. 

ramosutn,  282. 
Endospore,  225. 
Enteromorpha,   148,    195,   208,  214, 

341- 

acanthophora,  200. 
arctica.  203. 
aureola,  206. 
clathrata,  197,  199. 
compressa,  196,  201,  203. 


f.  subsimplex,  201. 
criuita,  196,  199. 
•  cruciata,  198. 
erecta,  200. 
fascia,  204. 
flexuosa,  203,  205. 
Hopkirkii,  198. 
intestiualis,    139,    203,   204,  205, 

206,  210. 
f.  clavata,  205. 
v.  crispa,  205. 
f.  cyliudracea,  205. 
f.  maxima,  204,  205. 
f.  tenuis,  205. 
linza,  206,  210,  216. 
f.  crispata,  206. 
f.  lanceolata,  206. 
marginata,  196,  202. 
jnicrococca,  204. 
f.  bullosa,  204. 
f.  subsalsa,  204. 
minima,  201,  204. 
f.  glacialis,  201. 
f.  rivularis,  201. 
percursa,  197,  198. 
plumosa,  198. 
polyclados,  202. 
prolifera,  199,  202. 
v.  arctica,  203. 
v.  trabeculata,  203. 
v.  tubulosa,  203. 
ramulosa,  200. 
salina,  202. 

v.  polyclados,  202. 
'  torta,  198. 

tubulosa,  203. 
Rntocladia. 

viridis,  279. 
Epicladia,  287. 

Flustrae,  280,  287. 
Epigynous,  224. 
Eremosphaera,  154. 
viridis,  154. 
v.  major,  155. 
v.  minor,  155. 
Eudorina,  133,  134. 
elegans,  134. 
stagnate,  134. 
Euglenopsis. 

subsalsa,  141. 
Euspirogyra,  107. 
Excentrosphaera,  155. 

viridis,  155. 
Exospore,  225. 
Exsiccatae,  81. 
Exterior  antheridium,  224. 
Filicoideae,  410. 


470 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No. "3 


Flagellates,  89,  92. 
Fucus,  185,  282. 
Fusola. 

viridis,  167. 
Gayella,  221. 

polyrhiza,  221. 
Gigartina. 

radula,  282. 

Globospora,  229,  243,  249,  262,  268. 
Gloeocapsa,  307. 

confluens,  307. 

fenestralis,  309. 

zostericola,  309. 
Gloeocystis,  143,  306,  307 ,  310. 

ampla,  309. 

chrysophthalma,  309. 

fenestralis,  309. 

gigas,  309. 
v.  rufescens,  309. 

Paroliniana,  309. 

rupestris,  308. 

scopulorum,  309. 

vesiculosa,  308. 

zostericola,  307,  309. 
Gloeothece. 

confluens,  307. 

distans,  307. 
Gloeotila. 

caldaria,  183. 
Gloiococcus,  309. 

tnucosus,  310. 
Gloiotaenium,  310. 

Loitlesbergerianum,  310. 
Gomontia,  86,  370. 

Holdenii,  371. 
"  polyrhiza,  370,  408. 
Gomontiaceae,  370. 
Gonatonema,  127. 

notabile,  127. 

ventricosum,  127. 
Gongrosira,  290. 

deBaryana,  290. 
Goniutn,  131. 

pectorale,  132. 

sociale,  132. 

tetras,  132. 
Grayemma, 

Menziesii,  365. 
Guignardia. 

alaskana,  220. 

Prasiolae,  220. 
Gynandrosporous,  224. 
Haematococcus,  130. 
Hooker ianus,  306. 
insignis,  306. 
lacustris,  130. 
pluvialis,  130. 


Halicystis,  372. 

ovalis,  372,  373. 
Halimeda,  87,  397,  431. 

discoidea,  400,  401. 

favulosa,  401. 

gracilis,  399. 

incrassata,  399. 
f.  monilis,  399. 
f.  tripartita,  399.          * 
/.  typica,  398. 

lacrimosa,  399. 

Monile,  399. 

Opuntia,  399,  400. 

scabra,  400,  401. 

siruulans,  401. 

tridens,  398,  402. 
f.  tripartita.  399. 
f.  typica,  398. 

Tuna,  400,  401. 
Halosphaeraceae,  154. 
Hansgirgia. 

flabelligera,  321. 
Herposteiraceae,  310. 
Herposteiron,  311. 

confervicola,  311. 

vermiculoides,  311. 
Heterokontae,  90,  91,  92. 
Hippuroideae,  410. 
Hormidiutn,  221. 

murale,  221. 

parietinum,  221. 
Hormiscia,  181,  182,  209,  367. 

collabens,  369. 

crassa,  369. 

flaccida. 

v.  caldaria,  183. 

Hartzii,  369. 

iiicrassata,  369. 

penicillifortnis,  185,  368. 

Wormskjoldii,  368. 
Hormospora,  187. 

mutabilis,  187. 

purpnrea,  187. 

scalariformis,  188. 
Hormotila,  167. 

nyicigena,  167. 
Hormotrich  u  m . 

bore  ale,  185. 

speciosum,  185,  368. 

Wormskjoldii,  368. 
Hyalotheca,  311. 
Hydra,  157. 
Hydrianum. 

heteromorphum,  150. 
Hydrocytiu  »i . 

acuminatum,  151. 
Hydrodictyaceae,  175. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA 


Hydrodictyon,  161,  175. 

reticulatum,  176.        * 
Hyella. 

caespitosa,  370. 
Hypogynous,  224. 
Idioandrosporous,  224. 
Ilea,  206. 

fulvescens,  204,  206. 
.Ineffigiata,  138. 

neglecta,  138. 

Instructions  for  collecting,  85. 
Interior  autheridium,  224. 
Iridaea,  148. 

laminarioides,  282,  287. 
Isokontae,  90. 
Keys,  83. 
Kirchneriella,  171. 

lunaris,  171. 

v.  Dianae,  171. 
Laminaria,  282,  324. 

longicruris,  286. 

Sinclairii,  283. 
Lateral  conjugation,  102. 
Laurencia. 

obtusa,  278. 
Leathesia. 

difformis,  284. 
Leiosperma,  102. 
Lemna. 

gibba,  147. 

minor,  147. 

trisulca,  146,  147. 
Lithodertua,  290. 
Lithothamuion,  372. 
Littorina. 

palliata,  280. 
Lunatia. 

heros,  292. 

Lycopodioideae,  410. 
Lyngbya,  198. 

aestuarii,  341. 

confervoides,  432. 
Macrandria,  229,  235,  243,  247. 
Macrandrous,  224. 
Mastigocoleus. 

testarum,  370. 
Mesocarpaceae,  121. 
Mesocarpicae,  122. 
Mesocarpus,  121. 

crassus,  125. 

macrosporus,  125. 

nummuloides,  123. 

parvulus,  123. 

pleurocarpus,  125. 

recur  vus,  123. 

robustus,  124. 


scalaris,  123. 
Mesogloia. 

divaricata,  284. 
Mesospore,  102,  225. 
Micrasterias. 

falcatus,  J57. 
Microchaete. 

grisea,  293. 
Microcladia. 

boreal  is,  345. 
Microcystis. 

Paroliniana,  309. 
Microdictyon,  283,  366,  367,  376. 

Agardhianum,  366. 

crassum,  366. 

umbilicatum,  366. 
Microspora,  96,  192. 

amoena,  185,  193,  330. 
f.  crassior,  193. 

crassior,  185,  193. 

floccosa,  194. 

Loefgrenii,  193. 

pachydernia,  193. 

quadrata,  194. 

stagnorutn,  193,  194. 

tumidula,  194. 

Willeana,  194. 

Wittrockii.  193. 
Microthamnion,  294. 

Kuetzingianuni,  294. 

strictissimuin,  295. 

v.  macrocystis,  295. 
Monoecious,  224. 
Monostroma,  139,  207,  219. 

angicava,  210. 

arcticum,  210. 

v.  intestiniforme,  210. 

Blyttii,  213. 

crepidinum,  211. 

cylindraceum,  210. 

fuscum,  207,  211,  213. 
f.  Blyttii,  213 
f.  splendens,  213. 

Grevillei,  209,  210. 
v.  intestiniforme,  210. 
v.  lubricum.  209. 
v.  Vahlii,  209,  210. 

groenlandicuui,  196,  207,  208. 

Lactuca,  209,  210. 

latissimum,  207,  211. 

leptodernium,  213. 

liibricum,  209. 

orbiculatum,  212. 
v.  variuni,  212. 

pulchrum,  211. 

quaternarium,  212. 


472 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 


saccodeum,  210. 

splendens,  213. 

thernialis,  214. 

undulatvmi,  211. 

v.  Farlowii,  211. 
Vahlii,  209. 

Wittrockii,  211. 

zostericolum,  213. 
Monozyga,  115. 
Mougeotia,  121,  122. 

calcarea,  127. 

capucina,  127. 

crassa,  125. 

delicatula,  124. 

divaricata,  124. 

elegantula,  126. 

genuflexa,  125. 

glyptosperma,  120. 

laetevirens,  125. 

levis,  124. 

macrospora,  125. 

minnesotensis,  124. 

uummuloides,  123. 

parvula,  123. 
v.  angusta,  123. 

quadrangulata,  126. 

quadrata,  126. 

radicans,  123. 

recurva,  123. 

robusta,  124. 

scalaris,  123. 

sphaerocarpa,  123. 

tenuis,  126. 
v.  minor,  126. 

verrucosa, 124. 

viridis,  126. 
Mycoidea. 

parasitica,  321. 
Myxonema . 

aestivale,  300. 

pmoenum,  299. 

attenuatum,  301. 

flagelliferuin,  299. 

glomeratum,  301. 

lubricum,  298. 
v.  varians,  298. 

nanunt,  300. 

stagnatile,  301. 

subsecunduin,  301. 

subuligerum,  299. 

tenue,  300. 

thennale,  300. 

ventricosum,  299. 
Mytilus. 

edulis,  144. 
Nannandres,  224. 
Nannandres  unicellulares,  262. 


Nannandria,  249. 
Nannandrous,  224. 
Nemalion. 

Andersonii,  284. 
multifidum,  284. 
Neotaeris,  380. 
annulata,  382. 
Cokeri,  382. 
dumetosa,  381,  382. 
Keller i,  382. 
niucosa,  381. 
Nephrocytium,  160. 
Agardhianuni,  161. 
Naegelii,  161. 
Nitella,  313 
Nomenclature,  84. 
Nylaudera,  320. 

tentaculata,  320. 
Ochlochaete,  288,  289. 
ferox,  288. 
hystrix,  288. 
Oedocladiuni,  223. 
Oedogoniaceae,  83,  88,  222. 
Oedogonium,  91,  200,  223,  281, 
acrosporum,  259,  260. 

v.  bathmidosporum,  260. 
f.  boreale,  259. 
v.  connectens,  259. 
v.  floridense,  260. 
Ahlstrandii,  247. 
apiculatum,  239. 
Areschougii,  263. 

f.  robustutn,  263. 
armigerum,  251,  252. 
aster,  250. 
autumnale,  246. 
Borisianum,  255,  256,  257. 
Boscii,  237. 
f.  dispar,  238. 
v.  occidentale,  238. 
Braunii,  249. 
capillare,  234,  235. 
capilliforme,  234. 
v.  australe,  234. 
f.  DeBaryanum.  235. 
f.  diversum,  235. 
f.  validum,  234. 
cardiacum,  230,  231,  232. 

v.  carbonicum,  231. 
cataractum,  266. 
concateuatum,  256,  257. 

v.  setigertim,  257. 
crassiusculum,  256. 

v.  idioandrosporum,  255. 
crassum,  240. 

f.  amplum,  241. 
crenulato-costatum,  239. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA 


473 


v.  aureum,  239. 

f.  cylindricum,  239. 
crispuni,  244,  246. 

v.  gracilescens,  245. 

f.  typicum,  245. 

v.  uruguayeuse,  245. 
cryptoporum,  229. 

v.  vulgare,  229. 
cyathigerum,  260,  262. 

f.  americanuni,  261. 

f.  oruatuin,  260. 
decipiens,  262. 
Donnellii,  252,  253. 
ecbinatuni,  251,  252. 
echinosperrnuni,  250. 

v.  horriduin,  250. 
flavescens,  249. 
fonticola,  264. 
foveolatum,  233. 
fragile,  232,  233,  251. 
franklinianuui,  231. 
geniculatum,  234. 
giganteum,  265. 
gracillimum,  247. 
grande,  241,  242,  243. 

v.  aequatoriale.  243. 
f.  hortense,  243. 

v.  angustum,  242. 
Howardii,  244. 
Huntii,  253. 
hystrix,  254. 
irregulare,  251. 
Landsboroughii,  241. 
Londinense,  266. 
longatuin,  258. 
Lundense,  258. 
macrandriutu,  258. 

v.  aeniulans,  258. 
Magnusii,  230. 
margaritiferum.  238. 
martinicense,  240. 
mexicanum,  243. 
niultisporum,  257. 
nobile,  248. 
nodulosum,  24?,  248,  262. 

v.  commune,  248. 
obesutn,  245. 
oboviforine,  241. 
obsoletutn,  230. 
obtruncatum,  264. 

v.  oblatum,  264. 
pachyandrium.  241. 
paludosum,  237. 

v.  americanuni,  237. 
Pithophorae,  244. 
plagiostomutn,  233. 

v.  gracilius,  233. 


platygynum,  264. 

plusiosporuni,  230,  231. 

pluviale,  264. 

polymorplntm,  232. 

princeps,  234. 

Pringsheitiiii,  246. 
v.  Nordstedtii,  247. 

punctato-striatum,  243,  244. 

punctatum,  240. 

pungens,  249,  251. 

pyriforme,  265,  266. 

Richterianum,  236. 

rivulare,  236. 
:.'.  major,  241. 

Rothii,  262,  263. 

rufescens,  229. 

subsp.  LundelHi,  229. 

sancti  thomae,  265. 

scrobiculatum,  234,  240. 

sexangulare,  253. 
v.  majus,  254. 

spirale,  253. 

stagnate,  235. 

stellatum,  252. 

suecicum,  230. 

taphrosporum,  239. 

undulatum,  261. 
f.  senegalense,  262. 

upsaliense,  235. 

varians,  232. 

Vaucherii,  232. 

vernale,  245. 

Wolleanum,  256. 
v.  concinnum.  257. 
f.  iusigne,  257. 
Oocystis,  159. 

Borgei,  160. 

crassa,  160. 

lacustris,  160. 

solitaria,  160. 

f.  major,  160. 
Oogonium  erect,  267. 
Oogonium  patent,  267. 
Operculata,  243,  247,  261,  262. 
Operculate,  225. 
Ophiocytium,  93. 

arbuscula,  95. 

capitatum,  94. 

circinatum,  94. 

cochleare,  94. 

cuspidatum,  95. 

gracilipes,  95. 

niajus,  94. 

parvulum,  94. 

v.  circinatum,  94. 
Ophrydium,  157. 
Ostreobium,  407,  408. 


474 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 


Quekettii,  408. 
Palmella,  136. 

ininiata,  137. 

v.  aequalis,  137. 
Palmellococcus,  158,  305. 

marinus,  159. 

miniatus,  159. 

thermalis,  159. 
Palrnodactylon,  140. 

simplex,  140. 

varium,  140. 
Palmodictyon,  310. 

viride,  310. 
Patidorina,  132. 

Morum,  132. 
Parthenospores,  105. 
Paspaloideae,  410. 
Pectinata,  102. 
Pediastrum,  161,  176. 

angulosum,  176,  178. 

biradiatum,  179. 

v.  etnarginatum,  179. 

Boryanum,  176,  177. 
v.  granulatum,  178. 
v.  uodulatum,  178. 

duplex,  179. 

v.  brachylobuui,  179. 
v.  clathratum,  179. 

Ehrenbergii,  179. 

forcipatum,  176,  177. 

pertusum,  179. 

rotula,  179. 

v.  emarginatum,  179. 

simplex,  177. 

v.  duodenarium,  177. 
v.  Sturtnii,  177. 

tetras,  179. 

tricornutum,  177. 

undulatum,  178. 

vagum,  176.  178. 
Pellucida,  376. 
Penicillus,  391,  396,  431. 

capitatus.  392,  393. 

dumetosus,  392. 

Lamourouxii,  392. 
v.  gracilis,  393. 

Phoenix,  393. 

pyriformis,  393. 
Petrocelis,  147.  152. 
Petrosiphon,  375. 

adhaerens,  375. 
Phycopeltis,  321. 
Phyllactidium,  321. 

tropicum,  321.- 
Phyllantoideae,  410. 
Phyllodictyon,  377. 
Phyllosiphon,  407,  408. 


Arisari,  408. 
Phyllosiphonaceae,  407. 
Pilinia,  86,  291 

endophytica,  292. 

Lunatiae,  292. 

inaritima,  293. 

minor,  292. 

Morsei,  293. 

Reinschii,  293. 

rimosa,  293. 
Piloboloideae,  422. 
Pithophora,  362. 

aequalis,  363. 

v.  floridensis,  363. 


Cleveana,  244,  280,  364. 

kewensis,  364. 

oedogonia,  363. 

v.  vaucherioides,  363. 

Roettleri,  364. 

varia,  364. 

Plagiosperrnicae,  122. 
Plagiospermum,  121. 

tenuc,  126. 
Plates,  81. 
Platydorina,  133. 

caudata,  134. 
Pleodorina,  132. 

californica,  133. 

illinoisensis,  133. 
Pleurocarpus,  125. 

columbianus,  125. 

mirabilis,  125 
Pleurococcaceae.  217. 
Pleurococcus,  304,  305. 

aquaticus,  305. 

Ktitzingii,  305. 

marinus,  159. 

regularis,  305. 

vulgaris,  284,  304,  305. 
Polychaetophora,  278. 

lamellosa,  278. 

simplex,  278. 
Polyedrium,  161. 

angulosum,  164. 

armatum,  165. 

enorme,  165. 

gigas,  165. 

gracile,  164. 
v.  tenue,  164. 

irregulare,  164. 

minimum,  163. 

minutum,  166. 

muticum,  163. 

pachydermum,  164. 

puncfulatum,  163. 

quadratum,  164. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA 


475 


(juadriciispidation,  164. 

rfcticulatiini,  163. 

tetniedricum,  165. 
:'.  longispinum,  165. 

tetragonum,  163. 

trigonmn,  162. 

v.  b  if  urea  tn  in,  165. 
r.  punctafuiii,  162. 
z1.  (ffragoninn,  163. 

t  u  in  id  u  I  u  in,  165. 

z1.  rotiindatuin,  165. 
Polyliedra,  175. 
Polysiphouia,  200. 
Pontederia,  88. 
Pore  inferior,  225. 
Pore  median,  225. 
Pore  superior,  225. 
Porifera,  229,  235,  249,  260. 
Poriferous,  225. 
Porphyra,  219,  220. 
Prasiuocladus,  87,  141. 

lubricus,  141. 

subsalsus,  141. 
Prasiola,  218,  222. 

borealis,  220. 

calophylla,  219. 

crispa,  218,  220. 

snbsp.  marina,  222. 

fluviatilis,  220. 

Gardneri,  221. 

mexicana,  220. 

Sa uteri,  220. 

tesselata,  220. 
Prasiolaceae,  217. 
Pringsheimia,  286,  287. 

scutata,  288. 
Protococcaceae,  142. 
Protococcahs,  91,  100,  142. 
Protococcus,  142,  305. 

ovalis,  142,  305. 

viridis,  159. 

r.  niiniatus,   159. 
Protodertna,  2lf. 

marinuru,  217. 

viride,  217. 
Protosiphon,  98,  153. 

botryoides,  99,  154. 
Protosiphonaceae,  153. 
Pseudendoclonium,  86,  284. 

submarinum,  284. 
Pseud odictyon,  282. 

geiiiculatutn,  283. 
Pseudo-Pleurococcus,  305. 

botryoides,  305. 

vulgar  is,  305. 
Racemosae,  423. 
Radiofilum,  188. 


apiculatum,  188. 
Ralfsia. 

Borneti,  284,  293. 
References,  81. 
Reinschiella,  95. 
cusfiidata,  95. 
setigcra,  158. 
Rhaphidiuni,  157. 
aciciilare,  158. 
Braunii,  158. 
convolutum,  158. 
falcaturn,  157. 

v.  aciculafe,  158. 

v.  fusiforine,  158. 
fasciculatum,  158. 
fractutn,  158. 
minutum,  171. 
polymorphitin,  157. 

rr.  aciciilare,  158. 
setigeruni,  158. 
Rhipilia. 

longicaulis,  391. 
Rhipocephalus,  392,  393,  431. 
Phoenix,  393. 

f.  brevifolius,  393. 

f.  longifolius,  393. 

f.  typicus,  393. 

Rhizocloniuni,  198,  326,  338,  353. 
antillarum,  329. 
Berggrenianum,  330. 
1  v.  dominicense,  330. 
capillare,  325. 
Casparyi,  330. 
crassipellitum,  330. 

v.  robustum,  330. 
crispum,  329,  330. 
erectum,  327. 
fluitans,  330. 
fontanuni,  330. 
fontinale,  330. 
hieroglyphicum,  329,  330. 

v.  aniericanmn,  329. 

v.  atrobrunneutn,  330. 

v.  Hosfordii,  329. 

v.  Kochianum,  330. 

v.  macromeres,  329. 
Hookeri,  330. 
Hosfordii,  329. 
Kerneri,  329. 
Kochianum,  328,  329. 
lacustre,  329. 

f.  americanum,  329. 
lanosum,  328. 
niajus,  330. 
occidental*,  330. 
pachydermxim,  327. 

v.  tenue,  327. 


476          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 


riparium,  327. 

v.  implexum,  328. 
v.  polyrhizurn,  328. 
v.  validum,  328. 
stagnale,  330. 
stagnorum,  330. 
tortuosum,  325,  328. 
f.  polyrhizum,  328. 
Rhodochytrium,  148. 

Spilanthidis,  148. 
Salicornia,  350. 
Salmacis,  115. 
Sarcopbyllis,  148. 
Scalarifortn  conjugation,  102. 
Scenedesmaceae,  155. 
Scenedesmus,  168. 
acutus,  168. 

v.  dimorphus,  169. 
antennatus,  169. 
v.  rectus,  169. 
bijuga,  168. 

v.  alternans,  168. 
v.  flexuosus,  168. 
bijugatus,  168. 

v,  flexuosus,  168. 
caudatus,  169. 
denticulatus,  169. 
dimorphus,  169. 
hystrix,  169. 
obliquus,  168. 

v.  dimorphus,  169. 
polymorphus,  169. 
obtusus,  168. 
quadricauda,  169. 
f.  abundans,  169. 
v.  ellipticus,  169. 
f.  horridus.  169. 
f.  setosus,  169. 
f.  typicus,  169. 
rotundatus,  169. 
Schizochlaniys,  16? . 

gelatinosa,  167. 
Schizogonium,  187,  218,  222. 
crenulatum,  218. 
crispum,  218. 
laetevirens,  186. 
murale,  218. 

v.  alpinum,  218. 
Schizomeris,  189. 
Leibleinii,  189. 
Schizonema,  148. 
Sciadium,  94. 
arbuscttla,  95. 
gracilipes,  95- 
Scrobiculala,  103. 
Scytosiphon,  284. 
Sedoideae,  411. 


Selenastrum,  171. 
Bibraianum,  171. 

minutum,  171. 
Sessiles,  423. 
Siphonales,  91,  385. 
Siphonocladiales,  91,  321. 
Siphonocladus,  362,  371,  374. 
membranaceus,  362,  371. 

rigidus,  374. 

tropicus,  374. 
Sirogonium,  119. 

ceylanicum,  119. 

sticticum,  119. 
Sorastrum,  173. 

bidentatum,  173. 

spinulosum,  173. 
Spartina,  185,  202. 
Sphacelaria. 

raceinosa,  147. 
Sphaerella,  130. 

lacustris,  130. 
Sphaerocarpus,  123. 

scalaris,  123. 
Sphaerocystis,  310. 

Schroeteri,  310. 
Sphaeroplea,  384. 

annulina,  384. 

Braunii,  385. 

crassisepta,  385. 
Sphaeropleaceae,  384. 
Sphaerospenmtm,  121. 
Spirogyra,  105,  200. 

adnata,  119. 

affinis,  113. 

bellis,  115. 

bifaria,  116. 

calospora.  118. 
f.  gracilior,  118. 
f.  major,  118. 

catenaeformis,  108. 

cotnmunis,  108,  109. 

condensata,  109. 
v.  Rusbvi,  110 

crassa,  112. 

decimina,  110. 

v.  submarina.  110. 
v.  triplicata,  110. 

diluta,  in. 

dubia,  115 

v.  longiarticulata,  115. 

elegans,  118. 

elongata,  119. 

flavescens,  113. 

fluviatilis,  114. 

fusco-alra,  109. 

gracilis,  114. 

Grevillt-ana.  117. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA 


477 


groenlandica,  117. 
Hantzschii,  118. 
Hassallii,  117. 
inflata,  116. 
insignis,  117. 
v.  elongata,  119. 
v.  Hantzschii,  118. 
Juergensii,  108. 
jugalis,  111. 
longata,  107,  119. 
lutetiana,  114. 
majitscula,  112. 

v.  bra chy meres,  112. 
maxima,  112. 

v.  inaequalis,  112. 
mirabilis,  113. 
neglecta.  114,  119. 
nitida,  110. 
orbicularis,  112. 
orthospira,  112. 
parvispora,  111. 
porticalis,  108.     • 

f.  minor,  108. 
protecta,  118. 
pulchella,  116. 
punctata,  115. 
quadrata,  116. 
quinina,  108. 
rivularis,  119. 
setiformis,  111. 
Spreeiana,  116. 
stictica,  119. 
subaequa,  119. 
subsalsa,  110. 
tenuissima,  115,  119. 
ternata,  114. 
varians,  108. 
Weberi,  116. 
Spirorbis,  370. 
Spongilla,  157. 
Spongomorpha,  331,  332,  346,  356, 

432. 

arcta,  209,  358,  359,  361. 
f.  conglutiuata,  359. 
v.  penicilliformis,  359. 
f.  pulvinata.  360. 
tduriuscula,  357. 
hystrix,  358. 
f.  debilis,  358. 
f.  littoralis.  358. 
f.  typica,  358. 
lanosa,  358. 

v.  uncialis,  359. 
rhizophora,  362. 
saxatilis,  360. 

v.  Chamissonis,  360. 
spinescens,  360,  361. 


vernalis,  357. 
Spongopsis. 

saccata,  356. 
Staurogenia. 

a  itciata,  170. 
Staurospermicae,  122. 
Staurospermutn,  121. 
capucimtni ,  127. 
quadratum,  126. 
viride,  126. 
Stephanokontae,  90. 
Stichpcoccus,  188,  189. 
bacillaris,  190. 

f.  confervoideus,  190. 
flaccidus,  191. 
fluitans,  191. 
marinus,  190. 
rivularis,  191. 
scopulinus,  190. 
subtilis,  191. 
Stigeoclonium,  284,    285,  295,  297, 

302. 

aestivale,  300. 
amoenum,  299. 
attenuatum,  301. 
flagelliferum,  299. 
glorneratum,  301. 
longipilus,  302. 
v.  minus,  302. 
lubricum,  298. 

v.  varians,  298. 
minus,  302. 
nanum,  300. 

f.  subsimplex,  300. 
stagnatile,  301,  302. 
subsecundum,  301. 
subuligerum,  299. 
tenue,  300. 

v.  lubricum,  298. 
thermale,  300. 
ventricosum,  299. 
Streblonema,  284. 
Struvea,  367,  371,  375. 
anastomosans,  376. 

v.  caracasana,  376. 
delicatula,  376. 
pulcherrima,  376. 
ramosa,  377. 
Subepigynous,  224. 
Subhypogynous,  224. 
Suffultory.  224. 
Tellamia,  280. 
contorta,  280. 
intricata,  281. 
Tenacula,  376. 
Tetraedron,  161. 
angulosum,  164. 


478 


TUFTS  COI/LEGE"  STUDIES,  Voi,.  II,  No.  3 


armatum,  165. 

v.  minus,  165. 
bifurcatum,  165. 
enorme,  165. 
gigas,  165. 
gracile,  164. 

v.  tenue,  164. 
minimum,  163. 
muticum,  163. 

f.  majus,  163. 

f.  punctulatutn,   163. 
pachyderruum,  164. 

f.  leptodermum,  165. 

f.  minus,  165. 
puuctulatum,  163. 

f.  rectangulare,  163. 
quadratuin,  164. 
quadricuspidatuni,  164. 

f.  inaequale    164. 
regulare,  165. 

v.  longispinum,  165. 
reticulatum,  163. 
tetragonum,  163. 
trigouum,  162. 

v.  puuctatum,  162. 
Tetraneina. 

percursum,  197. 
Tetraspora,  138,  167. 
bullosa,  139. 

v.  cylindracea,  139. 
cylindrica,  138. 

v.  extensa,  139. 
extensa,  139. 
gelatinosa,  139. 

f.  uniformis,  140. 
lubrica,   139. 

v.  lacunosa,  139. 
inacrospora,  140. 
Tetrasporaceae,  136. 
Thamuiastrum,  166. 

cruciatum,  166. 
Thuyoideae,  410. 
Trentepohlia,  315,  320. 
abietiua,  317. 
arborum,  318. 
aurea,  316,  317,  318. 

v.  Pittierii,  317. 

v.  polycarpa,  317. 

v.  subsimplex,  317. 
effusa,  318. 
lolithus,  319. 
lagenifera.  318. 
odorata,  319. 

v.  betulitia,  320. 

v.  utnbrina,  319. 
Pittierii,  317. 
polycarpa,  317. 


rigid  ula,  320. 

set  if  era,  318. 

Tuckermanni,  317. 

uinbrina,  319. 
v.  quercina,  319. 

uncinata,  316. 

villosa,  317. 

v.  brachymeris,  317. 

Wainioi,  318. 
Trentepohliaceae,  315. 
Tribonetna,  96. 

bombycinum,  96. 
f.  tenue,  96. 

minus,  97. 

nfricnlosiiin,  97. 
Trichosolen. 

aiitil/ant  in,  403. 
Trochiscia,  144. 

aciculifera,  145. 

arguta,  146. 

aspera,  145. 

granulata,  145. 

hirta,  145. 

obtusa,  146. 

Reinschii,  145. 

recticularis,  145. 

spor  aides,  145. 
Turnerella. 

Pennyi,  290. 
Tubuligerae,  422. 
Udotea,  394,  396,  430,  431. 

argentea,  396. 

conglutinata,  395. 

cyathiforniis,  395. 

flabellata,  396. 

Flabellum,  394,  395. 

luteo-fusca,  397. 

minima,  394.  432. 

spinulosa,  395. 

tomentosa,  394. 
Udotoideae,  386. 
Ulothrix,  181.  222,  301,  309. 

aequalis,  184. 

caldaria,  183. 

collabens,  369. 

consociata,  186. 

flacca,  185. 

flaccid  a,  188,  191. 
v,  genuina,  188. 

implexa,  185. 

isogona,  368. 

laetevireus,  186. 

naoniliformis,  184. 

oscillarina,  184. 

rivnlaris,  191. 

scutata,  432. 

subflaccida,  186. 


THE  GREEN  ALGAE  OF  NORTH  AMERICA          479 


subtilis,  191. 

r.  tenerrima,  183. 

:'.  thennafit  in,  183. 

v.  I'aHabi/is,  183. 
tenerrima,   183. 
tenuissima,  183. 
variabilis,  183. 

v.  marina,  190. 
zonata,  184,  /pj. 
Ulotrichaceae,  180. 
Ulotrichales,  91,  180. 
Ulva,  86,  87,  196,  214,  219,  220. 
californica,  215. 
clatluata,  199. 

T'.  raintilosa,  200. 

i'.  Rothiana. 

f,  pro  strata,  199. 
enteromorpha. 

:•.  intcstinalis,  204. 

v.  lanceolata,  206. 
fasciata,  210,  216. 

f.  caespitosa.  216. 

f.  expansa,  216. 

f.  lobata,  216. 

f.  taeniata,  216. 
gelatinosa,  139. 
ffopkirkii,  198. 
Lactuca,  209,  214,  216. 

t'.  Lactuca,  214. 

v.  latissiina,  215. 

v.  mesenteriforniis,  215. 

v.  rigida,  215. 
linza,  206. 
quatenaria,  212. 
thermalis,  214. 
Ulvaceae,  195. 
Ulvella,  285,  289,  290. 
americana,  289. 
confluens,  286. 
fucicola,  286. 
lens,  286. 
prostrata,  28?. 
Urococcus,  306. 
Foslieanus,  306. 

v.  ferrugineus,  307. 
Hookerianus,  306. 
insignis,  306. 
Uroneiua,  188. 

confervicola,  188. 
Urospora.  309,  368. 
Hartzii,  369. 
crassa,  369. 
incrassata,  369. 
Wormskjoldii,  368. 
Utricularia,  88. 
Valonia,  362,  372   374. 
aegagropila,  373. 


coufervoides,  373. 

oralis,  372. 

ventricosa,  373. 

verticillata,  373,  374. 

utricularis,  373. 
Valoniaceae,  371. 
Vaucheria,  91,  350,  422,  432. 

aversa,  424. 

clavata,  425. 

coronata,  429. 

dichotonia,  425. 

Dillwynii,  423. 

Gardner!,  428. 
f.  tenuis,  428. 

geminata,  427,  428. 
v.  racemosa.  427. 

haniata,  426,  427. 

intermedia,  429. 

litorea,  430. 

longipes,  428. 

ornithocephala,  424. 

orthocarpa,  425,  426. 

pachyderma,  423. 

piloboloides,  429. 
v.  compacta,  429. 

Pi /us,  425. 

polysperrua,  424. 

repens,  425,  426. 

sericea,  424. 

sessilis,  425,  426. 

sphaerospora,  429. 

terrestris,  426,  427. 

Thuretii,  424,  429,  430. 

luberosa,  431. 
v.  intermedia,  431. 
v.  minor,  431. 

velutina,  430. 
Vaucheriaceae,  421. 
Vaucherioideae,  410. 
Volvocaceae,  131. 
Volvocales,  91,  127. 
Volvox,  135. 

aureus,  135. 

globator,  135. 
Xanthophyll,  91. 
Zoochlorella,  143,  156,  305. 

conductrix,  157. 

parasitica,  157. 
Zostera. 

marina,  279,  288,  309. 
Zosteroideae,  410. 
Zygnema,  102,  311. 

anomalttm,  103. 
v.  crassum,  103. 

bifaria,  116. 

chalybeospermum,  104. 

cruciatum,'  104. 


480          TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 

cyanospermutn,   104.  Zygnemaceae,  88,  102. 

insigne,  104.  Zygogonium,  120. 
leiospermum,   104.  aequale,  121. 

pachydermum,  103.  Agardhii,  120. 

v.  confervoides,  103.  decussatum,  103. 

pectinatum,  103,  121.  ericetorum,  120. 

v.  anoinalum,  103.  v.  terrestre,  120. 

v.  decussatum,  103.  parvulum,  121. 

f.  terrestre,  103.  pectinatum,  103. 

Ralfsii,  121.  purpureum,  121. 

stellinum,  104. 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3. 


PLATE  II 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3. 


PLATK  III 


TUFTS  COLLKGE  STUDIES,  VOL.  II,  No.  3. 


PLATE  IV 


IHllllllW 


Tl'KTS    COLLEGE    STUDIES,    VOL.    II,    No.    3. 


PLATE  V 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3. 
49  -  50 


PLATE  VI 


6  2 


TUFTS  COT.T.KGK  STUDIES,  VOL.  II,  No.  3. 


66 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3. 

• 


PLATE  VIII 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3. 


PLATE  IX 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3. 

^jV**v  ~^F*^^* eso^^. 

'     '-  •••  .          ,;,     ;-.. 
- 


PLATE  X 


96 


TUFTS  COLLEGE  STUDIES,  VOL.  II,   No.  3. 


PLATE  XI 


102 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3.  PLATE  XII 


116 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3. 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3. 


PLATE  XIV 


127 


Tri-Ts  Cou.Kf.K  STTDII-S,   VOL.  II,   No.  3. 


PLATK  XV 


TITTS  COLLEGE  STI-DIKS.   Vol..  II,  No.  3. 


PLATS  XVI 


TVI--TS  COLLEGE  STUDIES,  VOL.  II,  No.  3- 


PLAT i.  XVII 


TUFTS  COLLEGE  STUDIES,  VOL.  II,  No.  3.          PLATE  XVIII 


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QK     Collins,  Frank  Shipley,  1848- 

571      ...  The  green  Algae  of  North  America. 

C59    1909. 


